chore: bump to v1.0.0-rc.1, reject trailing bytes, reject identity elemnts, more tests (#10)

Reviewed-on: #10
Co-authored-by: UneBaguette <[email protected]>
Co-committed-by: UneBaguette <[email protected]>

.cargo/license.rs

@@ -1,6 +1,7 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// Copyright (c) Meta Platforms, Inc. and affiliates.
 //
-// This source code is licensed under both the MIT license found in the
+// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree and the Apache
+// LICENSE-MIT file in the root directory of this source tree or the Apache
 // License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
+// of this source tree. You may select, at your option, one of the above-listed
+// licenses.

.gitea/workflows/ci.yml

@@ -0,0 +1,102 @@
+name: Rust CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    types: [opened, reopened, synchronize]
+
+concurrency:
+  group: ci-${{ gitea.ref }}
+  cancel-in-progress: true
+
+jobs:
+  fmt:
+    name: cargo fmt
+    runs-on: linux_amd64
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt
+      - name: Run cargo fmt
+        run: cargo fmt --all -- --check
+
+  clippy:
+    name: cargo clippy
+    runs-on: linux_amd64
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy
+      - name: Run cargo clippy
+        run: cargo clippy --all-features --all-targets -- -D warnings
+      - name: Run cargo doc
+        run: cargo doc --no-deps --document-private-items --features danger,std
+        env:
+          RUSTDOCFLAGS: -D warnings
+
+  test:
+    name: test (${{ matrix.toolchain }} / ${{ matrix.backend_feature || 'no backend' }} / ${{ matrix.frontend_feature || 'no frontend' }})
+    runs-on: linux_amd64
+    strategy:
+      fail-fast: false
+      matrix:
+        backend_feature:
+          - --features ristretto255-ciphersuite
+          - ""
+        frontend_feature:
+          - ""
+          - --features danger
+          - --features serde
+        toolchain:
+          - stable
+          - "1.87.0"
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: dtolnay/rust-toolchain@${{ matrix.toolchain }}
+      - name: Run cargo test
+        run: cargo test --no-default-features --lib --tests ${{ matrix.backend_feature }}
+      - name: Run cargo test with alloc
+        run: cargo test --no-default-features --lib --tests ${{ matrix.frontend_feature }} ${{ matrix.backend_feature }} --features alloc
+      - name: Run cargo test with std
+        run: cargo test --no-default-features --lib --tests ${{ matrix.frontend_feature }} ${{ matrix.backend_feature }} --features std
+      - name: Run cargo test with all features
+        run: cargo test --all-features
+
+  build-no-std:
+    name: no-std (${{ matrix.target }} / ${{ matrix.backend_feature || 'no backend' }})
+    runs-on: linux_amd64
+    strategy:
+      fail-fast: false
+      matrix:
+        target:
+          - wasm32-unknown-unknown
+          - thumbv6m-none-eabi
+        backend_feature:
+          - ""
+          - --features ristretto255-ciphersuite
+        frontend_feature:
+          - ""
+          - --features danger
+          - --features serde
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.target }}
+      - name: Build no-std
+        run: cargo build --verbose --target=${{ matrix.target }} --no-default-features ${{ matrix.frontend_feature }} ${{ matrix.backend_feature }}
+
+  audit:
+    name: cargo audit
+    runs-on: linux_amd64
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+      - uses: dtolnay/rust-toolchain@stable
+      - name: Install cargo-audit
+        run: cargo install cargo-audit
+      - name: Run cargo audit
+        run: cargo audit -D warnings

.gitea/workflows/publish.yml

@@ -0,0 +1,26 @@
+name: Publish
+
+on:
+  release:
+    types: [ published ]
+
+jobs:
+  publish:
+    runs-on: linux_amd64
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+
+      - uses: dtolnay/rust-toolchain@stable
+
+      - name: Login to crates.io
+        run: cargo login $CRATES_IO_TOKEN
+        env:
+          CRATES_IO_TOKEN: ${{ secrets.CRATES_IO_TOKEN }}
+
+      - name: Dry run publish
+        run: cargo publish --dry-run --manifest-path Cargo.toml
+
+      - name: Publish
+        run: cargo publish --manifest-path Cargo.toml
+        env:
+          CARGO_REGISTRY_TOKEN: ${{ secrets.CRATES_IO_TOKEN }}

.github/dependabot.yml

@@ -1,12 +0,0 @@
-version: 2
-
-updates:
-  - package-ecosystem: cargo
-    directory: /
-    schedule:
-      interval: daily
-
-  - package-ecosystem: github-actions
-    directory: /
-    schedule:
-      interval: daily

.github/workflows/main.yml

@@ -1,179 +0,0 @@
-name: Rust CI
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-    types: [opened, repoened, synchronize]
-
-jobs:
-  cargo-audit:
-    name: Audit
-    runs-on: ubuntu-latest
-    steps:
-      - name: Cache cargo-audit
-        uses: actions/cache@v3
-        with:
-          path: |
-            ~/.cargo/.crates.toml
-            ~/.cargo/.crates2.json
-            ~/.cargo/bin/cargo-audit
-          key: cargo-audit
-
-      - name: Install cargo-audit
-        run: cargo install cargo-audit
-
-      - name: Checkout sources
-        uses: actions/checkout@v3
-
-      - name: Run cargo audit
-        run: cargo audit -D warnings
-
-  test:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        backend_feature:
-          - --features ristretto255-ciphersuite
-          -
-        frontend_feature:
-          -
-          - --features danger
-          - --features serde
-        toolchain:
-          - stable
-          - 1.65.0
-    name: test
-    steps:
-      - name: Checkout sources
-        uses: actions/checkout@v3
-
-      - name: Install ${{ matrix.toolchain }} toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: ${{ matrix.toolchain }}
-          override: true
-
-      - name: Run cargo test
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --no-default-features ${{ matrix.backend_feature }}
-
-      - name: Run cargo test with alloc
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --no-default-features ${{ matrix.frontend_feature }},alloc ${{ matrix.backend_feature }}
-
-      - name: Run cargo test with std
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --no-default-features ${{ matrix.frontend_feature }},std ${{ matrix.backend_feature }}
-
-      - name: Run cargo test with all features enabled
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --all-features
-
-  build-no-std:
-    name: Build with no-std on ${{ matrix.target }}
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        target:
-          # for wasm
-          - wasm32-unknown-unknown
-          # for any no_std target
-          - thumbv6m-none-eabi
-        backend_feature:
-          -
-          - --features ristretto255-ciphersuite
-        frontend_feature:
-          -
-          - --features danger
-          - --features serde
-    steps:
-      - uses: actions/checkout@v3
-      - uses: hecrj/setup-rust-action@v1
-      - run: rustup target add ${{ matrix.target }}
-      - run: cargo build --verbose --target=${{ matrix.target }} --no-default-features ${{ matrix.frontend_feature }} ${{ matrix.backend_feature }}
-
-
-  clippy:
-    name: cargo clippy
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout sources
-        uses: actions/checkout@v3
-
-      - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-          components: clippy
-
-      - name: Run cargo clippy
-        uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: --all-features --all-targets -- -D warnings
-
-      - name: Run cargo doc
-        uses: actions-rs/cargo@v1
-        env:
-          RUSTDOCFLAGS: -D warnings
-        with:
-          command: doc
-          args: --no-deps --document-private-items --features danger,std
-
-
-  rustfmt:
-    name: cargo fmt
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout sources
-        uses: actions/checkout@v3
-
-      - name: Install nightly toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: nightly
-          override: true
-          components: rustfmt
-
-      - name: Run cargo fmt
-        uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
-
-  taplo:
-    name: Taplo
-    runs-on: ubuntu-latest
-    steps:
-      - name: Cache
-        uses: actions/cache@v3
-        with:
-          path: |
-            ~/.cargo/.crates.toml
-            ~/.cargo/.crates2.json
-            ~/.cargo/bin/taplo
-          key: taplo
-
-      - name: Install Taplo
-        run: cargo install taplo-cli
-
-      - name: Checkout sources
-        uses: actions/checkout@v3
-
-      - name: Run Taplo
-        run: taplo fmt --check

.github/workflows/publish.yml

@@ -1,28 +0,0 @@
-name: Publish
-
-on:
-  release:
-    types: [published]
-
-jobs:
-  publish:
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        os: [ubuntu-latest]
-
-    steps:
-    - uses: hecrj/setup-rust-action@v1
-      with:
-        rust-version: ${{ matrix.rust }}
-    - uses: actions/checkout@master
-    - name: Login to crates.io
-      run: cargo login $CRATES_IO_TOKEN
-      env:
-        CRATES_IO_TOKEN: ${{ secrets.crates_io_token }}
-    - name: Dry run publish voprf
-      run: cargo publish --dry-run --manifest-path Cargo.toml
-    - name: Publish voprf
-      run: cargo publish --manifest-path Cargo.toml
-      env:
-        CARGO_REGISTRY_TOKEN: ${{ secrets.crates_io_token }}

CHANGELOG.md

@@ -1,20 +1,92 @@
 # Changelog
 
+## 1.0.0-rc.1 (July 3, 2026)
+
+* Reject trailing bytes in all `deserialize` methods
+* Reject identity element in `deterministic_blind_unchecked` to prevent blinding bypass
+* Added roundtrip, trailing bytes, truncated, and empty input tests for serialization
+
+## 1.0.0-rc.0 (July 2, 2026)
+
+* Added missing license in Cargo manifest
+* Implement `zeroize` feature for `digest`, `hybrid-array` and `sha2`
+* Replaced license appendix in files while keeping original copyright
+
+## 1.0.0-pre.1 (July 2, 2026)
+
+* Simplified ciphersuite trait
+* Moved multiplication operator to SecurityLevel type in Group trait
+
+## 1.0.0-pre.0 (June 29, 2026)
+
+Forked from [facebook/voprf](https://github.com/facebook/voprf/) at `0.6.0-pre.1`.
+
+* MSRV bumped to 1.87
+* Migrated from `elliptic-curve 0.13` to `0.14`
+* Replaced `generic-array` with `hybrid-array 0.4`
+* Updated `digest` to 0.11, `rand_core` to 0.10, `rand` to 0.10, `sha2` to 0.11
+* Updated `p256`, `p384`, `p521` to `0.14`
+* Replaced `elliptic-curve/hash2curve` feature with standalone `hash2curve 0.14` crate
+* Removed `VoprfParameters` dependency to be replaced with `OprfParameters` + `GroupDigest`
+* Added `SecurityLevel` associated type to `Group` trait for generic hash bounds
+* Added `OkmLen` associated type to `Group` trait (`MapToCurve::Length`)
+* Updated `hash_to_scalar` to use `MapToCurve::Length` as OKM length per RFC 9380
+* Updated `random_scalar` for deterministic byte consumption with `rand_core 0.10`
+* Auto-impl `CipherSuite` for any `OprfParameters + Group` type via `OprfHash<T>`
+
+## 0.6.0-pre.1 (April 6, 2026)
+
+* MSRV bumped to 1.85
+* Updated rand_core dependency to 0.9
+* Updated rand dependency to 0.9
+* Updated subtle dependency to 2.6
+* Fixed docs issue
+
+## 0.6.0-pre.0 (November 8, 2025)
+
+* MSRV bumped to 1.83
+* Updated Ristretto255 random scalar generation
+* Updated generic-array to v1
+
+## 0.5.0 (March 6, 2024)
+
+* Just a version bump from v0.5.0-pre.7
+
+## 0.5.0-pre.7 (January 11, 2024)
+
+* Updated to be in sync with RFC 9497
+
+## 0.5.0-pre.6 (July 24, 2023)
+
+* Updated curve25519-dalek dependency to 4
+
+## 0.5.0-pre.5 (June 27, 2023)
+
+* Updated curve25519-dalek dependency to 4.0.0-rc.3
+
+## 0.5.0-pre.4 (May 20, 2023)
+
+* Updated curve25519-dalek dependency to 4.0.0-rc.2
+
 ## 0.5.0-pre.3 (March 4, 2023)
+
 * Updated to be in sync with draft-irtf-cfrg-voprf-19
 * Increased MSRV to 1.65
 * Updated p256 dependency to v0.13
 * Added p384 tests
 
 ## 0.5.0-pre.2 (February 3, 2023)
+
 * Increased MSRV to 1.60
 * Updated p256 dependency to v0.12
 * Updated curve25519-dalek dependency to 4.0.0-rc.1
 
 ## 0.5.0-pre.1 (December 19, 2022)
+
 * Updated curve25519-dalek dependency to 4.0.0-pre.5
 
 ## 0.4.0 (September 15, 2022)
+
 * Updated to be in sync with draft-irtf-cfrg-voprf-11, with
   the addition of the POPRF mode
 * Adds the evaluate() function to the servers to calculate the output of the OPRF

CODE_OF_CONDUCT.md

@@ -1,76 +0,0 @@
-# Code of Conduct
-
-## Our Pledge
-
-In the interest of fostering an open and welcoming environment, we as
-contributors and maintainers pledge to make participation in our project and
-our community a harassment-free experience for everyone, regardless of age, body
-size, disability, ethnicity, sex characteristics, gender identity and expression,
-level of experience, education, socio-economic status, nationality, personal
-appearance, race, religion, or sexual identity and orientation.
-
-## Our Standards
-
-Examples of behavior that contributes to creating a positive environment
-include:
-
-* Using welcoming and inclusive language
-* Being respectful of differing viewpoints and experiences
-* Gracefully accepting constructive criticism
-* Focusing on what is best for the community
-* Showing empathy towards other community members
-
-Examples of unacceptable behavior by participants include:
-
-* The use of sexualized language or imagery and unwelcome sexual attention or
-  advances
-* Trolling, insulting/derogatory comments, and personal or political attacks
-* Public or private harassment
-* Publishing others' private information, such as a physical or electronic
-  address, without explicit permission
-* Other conduct which could reasonably be considered inappropriate in a
-  professional setting
-
-## Our Responsibilities
-
-Project maintainers are responsible for clarifying the standards of acceptable
-behavior and are expected to take appropriate and fair corrective action in
-response to any instances of unacceptable behavior.
-
-Project maintainers have the right and responsibility to remove, edit, or
-reject comments, commits, code, wiki edits, issues, and other contributions
-that are not aligned to this Code of Conduct, or to ban temporarily or
-permanently any contributor for other behaviors that they deem inappropriate,
-threatening, offensive, or harmful.
-
-## Scope
-
-This Code of Conduct applies within all project spaces, and it also applies when
-an individual is representing the project or its community in public spaces.
-Examples of representing a project or community include using an official
-project e-mail address, posting via an official social media account, or acting
-as an appointed representative at an online or offline event. Representation of
-a project may be further defined and clarified by project maintainers.
-
-## Enforcement
-
-Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported by contacting the project team at <opensource-conduct@fb.com>. All
-complaints will be reviewed and investigated and will result in a response that
-is deemed necessary and appropriate to the circumstances. The project team is
-obligated to maintain confidentiality with regard to the reporter of an incident.
-Further details of specific enforcement policies may be posted separately.
-
-Project maintainers who do not follow or enforce the Code of Conduct in good
-faith may face temporary or permanent repercussions as determined by other
-members of the project's leadership.
-
-## Attribution
-
-This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
-available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
-
-[homepage]: https://www.contributor-covenant.org
-
-For answers to common questions about this code of conduct, see
-https://www.contributor-covenant.org/faq

CONTRIBUTING.md

@@ -2,29 +2,11 @@
 We want to make contributing to this project as easy and transparent as
 possible.
 
-## Pull Requests
-We actively welcome your pull requests.
-
-1. Fork the repo and create your branch from `main`.
-2. If you've added code that should be tested, add tests.
-3. If you've changed APIs, update the documentation.
-4. Ensure the test suite passes.
-5. If you haven't already, complete the Contributor License Agreement ("CLA").
-
-## Contributor License Agreement ("CLA")
-In order to accept your pull request, we need you to submit a CLA. You only need
-to do this once to work on any of Facebook's open source projects.
-
-Complete your CLA here: <https://code.facebook.com/cla>
-
 ## Issues
 We use GitHub issues to track public bugs. Please ensure your description is
 clear and has sufficient instructions to be able to reproduce the issue.
 
-Facebook has a [bounty program](https://www.facebook.com/whitehat/) for the safe
-disclosure of security bugs. In those cases, please go through the process
-outlined on that page and do not file a public issue.
-
 ## License
-By contributing to voprf, you agree that your contributions will be
+By contributing to voprf-vx, you agree that your contributions will be
-licensed under the LICENSE file in the root directory of this source tree.
+licensed under both the LICENSE-MIT and LICENSE-APACHE files in the root
+directory of this source tree.

Cargo.toml

@@ -1,65 +1,67 @@
 [package]
-authors = ["Kevin Lewi <[email protected]>"]
+authors = ["VexaHub Developers", "Kevin Lewi <[email protected]>"]
 categories = ["no-std", "algorithms", "cryptography"]
 description = "An implementation of a verifiable oblivious pseudorandom function (VOPRF)"
-edition = "2021"
+edition = "2024"
-keywords = ["oprf"]
+keywords = ["oprf", "voprf", "cryptography", "oblivious-prf"]
-license = "MIT"
+license = "MIT OR Apache-2.0"
-name = "voprf"
+name = "voprf-vx"
 readme = "README.md"
-repository = "https://github.com/facebook/voprf/"
+repository = "https://github.com/vexahub/voprf-vx/"
-rust-version = "1.65"
+rust-version = "1.87"
-version = "0.5.0-pre.3"
+version = "1.0.0-rc.1"
 
 [features]
 alloc = []
 danger = []
+doctest = ["dep:p256", "dep:sha2"]
 default = ["ristretto255-ciphersuite", "dep:serde"]
-ristretto255 = ["dep:curve25519-dalek", "generic-array/more_lengths"]
+ristretto255 = ["dep:curve25519-dalek"]
 ristretto255-ciphersuite = ["ristretto255", "dep:sha2"]
-serde = ["generic-array/serde", "dep:serde"]
+serde = ["curve25519-dalek?/serde", "hybrid-array/serde", "dep:serde"]
 std = ["alloc"]
 
 [dependencies]
-curve25519-dalek = { version = "=4.0.0-rc.1", default-features = false, features = [
+curve25519-dalek = { version = "5.0.0-rc.1", default-features = false, features = ["rand_core", "zeroize"], optional = true }
-  "rand_core",
-  "zeroize",
-], optional = true }
 derive-where = { version = "1", features = ["zeroize-on-drop"] }
-digest = "0.10"
+digest = { version = "0.11", features = ["zeroize"] }
 displaydoc = { version = "0.2", default-features = false }
-elliptic-curve = { version = "0.13", features = [
+elliptic-curve = { version = "0.14", features = [
-  "hash2curve",
+    "sec1",
-  "sec1",
-  "voprf",
 ] }
-generic-array = "0.14"
+hash2curve = "0.14"
-rand_core = { version = "0.6", default-features = false }
+hybrid-array = { version = "0.4", features = ["zeroize"] }
+rand_core = { version = "0.10", default-features = false }
 serde = { version = "1", default-features = false, features = [
-  "derive",
+    "derive",
 ], optional = true }
-sha2 = { version = "0.10", default-features = false, optional = true }
+sha2 = { version = "0.11", default-features = false, features = ["zeroize"], optional = true }
-subtle = { version = "2.3", default-features = false }
+p256 = { version = "0.14.0-rc.15", default-features = false, features = ["hash2curve", "oprf"], optional = true }
+subtle = { version = "2.6", default-features = false }
 zeroize = { version = "1.5", default-features = false }
 
 [dev-dependencies]
-generic-array = { version = "0.14", features = ["more_lengths"] }
 hex = "0.4"
-p256 = { version = "0.13", default-features = false, features = [
+p256 = { version = "0.14.0-rc.15", default-features = false, features = [
-  "hash2curve",
+    "hash2curve",
-  "voprf",
+    "oprf",
 ] }
-p384 = { version = "0.13", default-features = false, features = [
+p384 = { version = "0.14.0-rc.15", default-features = false, features = [
-  "hash2curve",
+    "hash2curve",
-  "voprf",
+    "oprf",
+] }
+p521 = { version = "0.14.0-rc.15", default-features = false, features = [
+    "hash2curve",
+    "oprf",
 ] }
 proptest = "1"
-rand = "0.8"
+rand = "0.10"
 regex = "1"
 serde_json = "1"
-sha2 = "0.10"
+sha2 = "0.11"
 
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
 targets = []
+features = ["doctest"]

LICENSE

@@ -1,12 +0,0 @@
-## License
-
-Licensed under either of
- * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
- * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
-at your option.
-
-### Contribution
-
-Unless you explicitly state otherwise, any contribution intentionally submitted
-for inclusion in the work by you, as defined in the Apache-2.0 license, shall
-be dual licensed as above, without any additional terms or conditions.

README.md

@@ -1,14 +1,14 @@
-# voprf ![Build Status](https://github.com/novifinancial/voprf/workflows/Rust%20CI/badge.svg)
+# voprf
 An implementation of a (verifiable) oblivious pseudorandom function (VOPRF)
 
 A VOPRF is a verifiable oblivious pseudorandom function, a protocol between a client and a server. The regular (non-verifiable) OPRF is also supported in this implementation.
 
-This implementation is based on the [Internet Draft for VOPRF](https://github.com/cfrg/draft-irtf-cfrg-voprf).
+This implementation is based on [RFC 9497](https://www.rfc-editor.org/rfc/rfc9497).
 
 Documentation
 -------------
 
-The API can be found [here](https://docs.rs/voprf/) along with an example for usage.
+The API can be found [here](https://docs.rs/voprf-vx/) along with an example for usage.
 
 Installation
 ------------
@@ -16,20 +16,24 @@ Installation
 Add the following line to the dependencies of your `Cargo.toml`:
 
 ```
-voprf = "0.5.0-pre.3"
+voprf = { package = "voprf-vx", version = "1.0.0-rc.1" }
 ```
 
 ### Minimum Supported Rust Version
 
-Rust **1.65** or higher.
+Rust **1.87** or higher.
 
 Contributors
 ------------
 
-The author of this code is Kevin Lewi ([@kevinlewi](https://github.com/kevinlewi)).
+This is a fork of [facebook/voprf](https://github.com/facebook/voprf/) maintained by [VexaHub](https://github.com/vexahub).
+
+The original author is Kevin Lewi ([@kevinlewi](https://github.com/kevinlewi)).
 To learn more about contributing to this project, [see this document](./CONTRIBUTING.md).
 
 License
 -------
 
-This project is [licensed](./LICENSE) under either Apache 2.0 or MIT, at your option.
+This project is dual-licensed under either the [MIT license](./LICENSE-MIT)
+or the [Apache License, Version 2.0](./LICENSE-APACHE).
+You may select, at your option, one of the above-listed licenses.

renovate.json

@@ -0,0 +1,30 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended"
+  ],
+  "dependencyDashboard": true,
+  "osvVulnerabilityAlerts": true,
+  "rangeStrategy": "auto",
+  "packageRules": [
+    {
+      "matchManagers": [
+        "cargo"
+      ],
+      "groupName": "rust deps"
+    },
+    {
+      "matchManagers": [
+        "cargo"
+      ],
+      "matchUpdateTypes": [
+        "major"
+      ],
+      "automerge": false
+    }
+  ],
+  "lockFileMaintenance": {
+    "enabled": true
+  },
+  "configMigration": true
+}

rustfmt.toml

@@ -1,8 +1 @@
-format_code_in_doc_comments = true
-format_strings = true
-group_imports = "StdExternalCrate"
-imports_granularity = "Module"
-license_template_path = ".cargo/license.rs"
 newline_style = "Unix"
-unstable_features = true
-wrap_comments = true

src/ciphersuite.rs

@@ -1,28 +1,28 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Defines the CipherSuite trait to specify the underlying primitives for VOPRF
 
-use digest::core_api::BlockSizeUser;
-use digest::{FixedOutput, HashMarker, OutputSizeUser};
-use elliptic_curve::VoprfParameters;
-use generic_array::typenum::{IsLess, IsLessOrEqual, U256};
-
 use crate::Group;
+use digest::block_api::BlockSizeUser;
+use digest::typenum::{IsLess, IsLessOrEqual, U256};
+use digest::{FixedOutput, HashMarker, OutputSizeUser};
+use hash2curve::{ExpandMsg, GroupDigest, MapToCurve, OprfParameters};
+use hybrid_array::ArraySize;
+use hybrid_array::typenum::{IsGreaterOrEqual, Prod, True, U2};
 
 /// Configures the underlying primitives used in VOPRF
 pub trait CipherSuite
 where
-    <Self::Hash as OutputSizeUser>::OutputSize:
+    <Self::Hash as OutputSizeUser>::OutputSize: ArraySize
-        IsLess<U256> + IsLessOrEqual<<Self::Hash as BlockSizeUser>::BlockSize>,
+        + IsLess<U256>
+        + IsLessOrEqual<<Self::Hash as BlockSizeUser>::BlockSize, Output = True>
+        + IsGreaterOrEqual<Prod<<Self::Group as Group>::SecurityLevel, U2>, Output = True>,
 {
     /// The ciphersuite identifier as dictated by
-    /// <https://datatracker.ietf.org/doc/draft-irtf-cfrg-voprf/>
+    /// <https://www.rfc-editor.org/rfc/rfc9497>
-    const ID: &'static str;
+    const ID: &'static [u8];
 
     /// A finite cyclic group along with a point representation that allows some
     /// customization on how to hash an input to a curve point. See [`Group`].
@@ -33,16 +33,20 @@ where
     type Hash: BlockSizeUser + Default + FixedOutput + HashMarker;
 }
 
-impl<T: VoprfParameters> CipherSuite for T
+/// The hash function associated with a curve's OPRF `expand_message` implementation.
+type OprfHash<T> =
+    <<T as GroupDigest>::ExpandMsg as ExpandMsg<<T as MapToCurve>::SecurityLevel>>::Hash;
+
+impl<T: OprfParameters> CipherSuite for T
 where
     T: Group,
-    T::Hash: BlockSizeUser + Default + FixedOutput + HashMarker,
+    OprfHash<T>: BlockSizeUser + Default + FixedOutput + HashMarker,
-    <T::Hash as OutputSizeUser>::OutputSize:
+    <OprfHash<T> as OutputSizeUser>::OutputSize: ArraySize
-        IsLess<U256> + IsLessOrEqual<<T::Hash as BlockSizeUser>::BlockSize>,
+        + IsLess<U256>
+        + IsLessOrEqual<<OprfHash<T> as BlockSizeUser>::BlockSize, Output = True>
+        + IsGreaterOrEqual<Prod<<T as Group>::SecurityLevel, U2>, Output = True>,
 {
-    const ID: &'static str = T::ID;
+    const ID: &'static [u8] = T::ID;
-
     type Group = T;
-
+    type Hash = OprfHash<T>;
-    type Hash = T::Hash;
 }

src/common.rs

@@ -1,9 +1,6 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Common functionality between multiple OPRF modes.
 
@@ -11,12 +8,10 @@ use core::convert::TryFrom;
 use core::ops::Add;
 
 use derive_where::derive_where;
-use digest::core_api::BlockSizeUser;
 use digest::{Digest, Output, OutputSizeUser};
-use generic_array::sequence::Concat;
+use hybrid_array::typenum::{IsLess, U2, U9, U256, Unsigned};
-use generic_array::typenum::{IsLess, IsLessOrEqual, Unsigned, U2, U256, U9};
+use hybrid_array::{Array, ArrayN, ArraySize};
-use generic_array::{ArrayLength, GenericArray};
+use rand_core::{TryCryptoRng, TryRng};
-use rand_core::{CryptoRng, RngCore};
 use subtle::ConstantTimeEq;
 
 #[cfg(feature = "serde")]
@@ -29,14 +24,14 @@ use crate::{CipherSuite, Error, Group, InternalError, Result};
 ///////////////
 
 pub(crate) const STR_FINALIZE: [u8; 8] = *b"Finalize";
-pub(crate) const STR_SEED: [u8; 5] = *b"Seed-";
+pub(crate) const STR_SEED: ArrayN<u8, 5> = Array(*b"Seed-");
-pub(crate) const STR_DERIVE_KEYPAIR: [u8; 13] = *b"DeriveKeyPair";
+pub(crate) const STR_DERIVE_KEYPAIR: ArrayN<u8, 13> = Array(*b"DeriveKeyPair");
 pub(crate) const STR_COMPOSITE: [u8; 9] = *b"Composite";
 pub(crate) const STR_CHALLENGE: [u8; 9] = *b"Challenge";
 pub(crate) const STR_INFO: [u8; 4] = *b"Info";
 pub(crate) const STR_OPRF: [u8; 7] = *b"OPRFV1-";
-pub(crate) const STR_HASH_TO_SCALAR: [u8; 13] = *b"HashToScalar-";
+pub(crate) const STR_HASH_TO_SCALAR: ArrayN<u8, 13> = Array(*b"HashToScalar-");
-pub(crate) const STR_HASH_TO_GROUP: [u8; 12] = *b"HashToGroup-";
+pub(crate) const STR_HASH_TO_GROUP: ArrayN<u8, 12> = Array(*b"HashToGroup-");
 
 /// Determines the mode of operation (either base mode or verifiable mode). This
 /// is only used for custom implementations for [`Group`].
@@ -78,10 +73,7 @@ impl Mode {
 pub struct BlindedElement<CS: CipherSuite>(
     #[cfg_attr(feature = "serde", serde(with = "Element::<CS::Group>"))]
     pub(crate)  <CS::Group as Group>::Elem,
-)
+);
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>;
 
 /// The server's response to the [BlindedElement] message from a client (either
 /// verifiable or not) to a server (either verifiable or not).
@@ -95,10 +87,7 @@ where
 pub struct EvaluationElement<CS: CipherSuite>(
     #[cfg_attr(feature = "serde", serde(with = "Element::<CS::Group>"))]
     pub(crate)  <CS::Group as Group>::Elem,
-)
+);
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>;
 
 /// Contains prepared [`EvaluationElement`]s by a server batch evaluate
 /// preparation.
@@ -109,10 +98,7 @@ where
     derive(serde::Deserialize, serde::Serialize),
     serde(bound = "")
 )]
-pub struct PreparedEvaluationElement<CS: CipherSuite>(pub(crate) EvaluationElement<CS>)
+pub struct PreparedEvaluationElement<CS: CipherSuite>(pub(crate) EvaluationElement<CS>);
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>;
 
 /// A proof produced by a server that the OPRF output matches against a server
 /// public key.
@@ -123,11 +109,7 @@ where
     derive(serde::Deserialize, serde::Serialize),
     serde(bound = "")
 )]
-pub struct Proof<CS: CipherSuite>
+pub struct Proof<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
     pub(crate) c_scalar: <CS::Group as Group>::Scalar,
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
@@ -141,24 +123,20 @@ where
 
 /// Can only fail with [`Error::Batch`].
 #[allow(clippy::many_single_char_names)]
-pub(crate) fn generate_proof<CS: CipherSuite, R: RngCore + CryptoRng>(
+pub(crate) fn generate_proof<CS: CipherSuite, R: TryRng + TryCryptoRng>(
     rng: &mut R,
     k: <CS::Group as Group>::Scalar,
     a: <CS::Group as Group>::Elem,
     b: <CS::Group as Group>::Elem,
-    cs: impl Iterator<Item = <CS::Group as Group>::Elem> + ExactSizeIterator,
+    cs: impl ExactSizeIterator<Item = <CS::Group as Group>::Elem>,
-    ds: impl Iterator<Item = <CS::Group as Group>::Elem> + ExactSizeIterator,
+    ds: impl ExactSizeIterator<Item = <CS::Group as Group>::Elem>,
     mode: Mode,
-) -> Result<Proof<CS>>
+) -> Result<Proof<CS>> {
-where
+    // https://www.rfc-editor.org/rfc/rfc9497#section-2.2.1
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
-    // https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-11.html#section-2.2.1
 
     let (m, z) = compute_composites::<CS, _, _>(Some(k), b, cs, ds, mode)?;
 
-    let r = CS::Group::random_scalar(rng);
+    let r = CS::Group::random_scalar(rng)?;
     let t2 = a * &r;
     let t3 = m * &r;
 
@@ -195,7 +173,7 @@ where
         &STR_CHALLENGE,
     ];
 
-    let dst = Dst::new::<CS, _, _>(STR_HASH_TO_SCALAR, mode);
+    let dst = Dst::new::<CS, _>(STR_HASH_TO_SCALAR, mode);
     // This can't fail, the size of the `input` is known.
     let c_scalar = CS::Group::hash_to_scalar::<CS::Hash>(&h2_input, &dst.as_dst()).unwrap();
     let s_scalar = r - &(c_scalar * &k);
@@ -208,16 +186,12 @@ where
 pub(crate) fn verify_proof<CS: CipherSuite>(
     a: <CS::Group as Group>::Elem,
     b: <CS::Group as Group>::Elem,
-    cs: impl Iterator<Item = <CS::Group as Group>::Elem> + ExactSizeIterator,
+    cs: impl ExactSizeIterator<Item = <CS::Group as Group>::Elem>,
-    ds: impl Iterator<Item = <CS::Group as Group>::Elem> + ExactSizeIterator,
+    ds: impl ExactSizeIterator<Item = <CS::Group as Group>::Elem>,
     proof: &Proof<CS>,
     mode: Mode,
-) -> Result<()>
+) -> Result<()> {
-where
+    // https://www.rfc-editor.org/rfc/rfc9497#section-2.2.2
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
-    // https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-11.html#section-2.2.2
     let (m, z) = compute_composites::<CS, _, _>(None, b, cs, ds, mode)?;
     let t2 = (a * &proof.s_scalar) + &(b * &proof.c_scalar);
     let t3 = (m * &proof.s_scalar) + &(z * &proof.c_scalar);
@@ -255,7 +229,7 @@ where
         &STR_CHALLENGE,
     ];
 
-    let dst = Dst::new::<CS, _, _>(STR_HASH_TO_SCALAR, mode);
+    let dst = Dst::new::<CS, _>(STR_HASH_TO_SCALAR, mode);
     // This can't fail, the size of the `input` is known.
     let c = CS::Group::hash_to_scalar::<CS::Hash>(&h2_input, &dst.as_dst()).unwrap();
 
@@ -281,12 +255,8 @@ fn compute_composites<
     c_slice: IC,
     d_slice: ID,
     mode: Mode,
-) -> Result<ComputeCompositesResult<CS>>
+) -> Result<ComputeCompositesResult<CS>> {
-where
+    // https://www.rfc-editor.org/rfc/rfc9497#section-2.2.1
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
-    // https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-11.html#section-2.2.1
 
     let elem_len = <CS::Group as Group>::ElemLen::U16.to_be_bytes();
 
@@ -297,7 +267,7 @@ where
     let len = u16::try_from(c_slice.len()).map_err(|_| Error::Batch)?;
 
     // seedDST = "Seed-" || contextString
-    let seed_dst = Dst::new::<CS, _, _>(STR_SEED, mode);
+    let seed_dst = Dst::new::<CS, _>(STR_SEED, mode);
 
     // h1Input = I2OSP(len(Bm), 2) || Bm ||
     //           I2OSP(len(seedDST), 2) || seedDST
@@ -308,7 +278,7 @@ where
         .chain_update(seed_dst.i2osp_2())
         .chain_update_multi(&seed_dst.as_dst())
         .finalize();
-    let seed_len = i2osp_2_array(&seed);
+    let seed_len = i2osp_2_array::<<CS::Hash as OutputSizeUser>::OutputSize>();
 
     let mut m = CS::Group::identity_elem();
     let mut z = CS::Group::identity_elem();
@@ -333,7 +303,7 @@ where
             &STR_COMPOSITE,
         ];
 
-        let dst = Dst::new::<CS, _, _>(STR_HASH_TO_SCALAR, mode);
+        let dst = Dst::new::<CS, _>(STR_HASH_TO_SCALAR, mode);
         // This can't fail, the size of the `input` is known.
         let di = CS::Group::hash_to_scalar::<CS::Hash>(&h2_input, &dst.as_dst()).unwrap();
         m = c * &di + &m;
@@ -361,12 +331,8 @@ pub(crate) fn derive_key_internal<CS: CipherSuite>(
     seed: &[u8],
     info: &[u8],
     mode: Mode,
-) -> Result<<CS::Group as Group>::Scalar, Error>
+) -> Result<<CS::Group as Group>::Scalar, Error> {
-where
+    let dst = Dst::new::<CS, _>(STR_DERIVE_KEYPAIR, mode);
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
-    let dst = Dst::new::<CS, _, _>(STR_DERIVE_KEYPAIR, mode);
 
     let info_len = i2osp_2(info.len()).map_err(|_| Error::DeriveKeyPair)?;
 
@@ -399,11 +365,7 @@ pub fn derive_key<CS: CipherSuite>(
     seed: &[u8],
     info: &[u8],
     mode: Mode,
-) -> Result<<CS::Group as Group>::Scalar, Error>
+) -> Result<<CS::Group as Group>::Scalar, Error> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     derive_key_internal::<CS>(seed, info, mode)
 }
 
@@ -417,11 +379,7 @@ pub(crate) fn derive_keypair<CS: CipherSuite>(
     seed: &[u8],
     info: &[u8],
     mode: Mode,
-) -> Result<DeriveKeypairResult<CS>, Error>
+) -> Result<DeriveKeypairResult<CS>, Error> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     let sk_s = derive_key_internal::<CS>(seed, info, mode)?;
     let pk_s = CS::Group::base_elem() * &sk_s;
 
@@ -437,12 +395,14 @@ pub(crate) fn deterministic_blind_unchecked<CS: CipherSuite>(
     input: &[u8],
     blind: &<CS::Group as Group>::Scalar,
     mode: Mode,
-) -> Result<<CS::Group as Group>::Elem>
+) -> Result<<CS::Group as Group>::Elem> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     let hashed_point = hash_to_group::<CS>(input, mode)?;
+
+    // Identity element would nullify blinding, revealing the input.
+    if CS::Group::is_identity_elem(hashed_point).into() {
+        return Err(Error::Input);
+    }
+
     Ok(hashed_point * blind)
 }
 
@@ -450,12 +410,8 @@ where
 pub(crate) fn hash_to_group<CS: CipherSuite>(
     input: &[u8],
     mode: Mode,
-) -> Result<<CS::Group as Group>::Elem>
+) -> Result<<CS::Group as Group>::Elem> {
-where
+    let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, mode);
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
-    let dst = Dst::new::<CS, _, _>(STR_HASH_TO_GROUP, mode);
     CS::Group::hash_to_curve::<CS::Hash>(&[input], &dst.as_dst()).map_err(|_| Error::Input)
 }
 
@@ -464,12 +420,8 @@ where
 pub(crate) fn server_evaluate_hash_input<CS: CipherSuite>(
     input: &[u8],
     info: Option<&[u8]>,
-    issued_element: GenericArray<u8, <<CS as CipherSuite>::Group as Group>::ElemLen>,
+    issued_element: Array<u8, <<CS as CipherSuite>::Group as Group>::ElemLen>,
-) -> Result<Output<CS::Hash>>
+) -> Result<Output<CS::Hash>> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     // OPRF & VOPRF
     // hashInput = I2OSP(len(input), 2) || input ||
     //             I2OSP(len(issuedElement), 2) || issuedElement ||
@@ -491,31 +443,28 @@ where
             .chain_update(info.as_ref());
     }
     Ok(hash
-        .chain_update(i2osp_2(issued_element.as_ref().len()).map_err(|_| Error::Input)?)
+        .chain_update(i2osp_2(issued_element.as_slice().len()).map_err(|_| Error::Input)?)
         .chain_update(issued_element)
         .chain_update(STR_FINALIZE)
         .finalize())
 }
 
-pub(crate) struct Dst<L: ArrayLength<u8>> {
+pub(crate) struct Dst<L: ArraySize> {
-    dst_1: GenericArray<u8, L>,
+    dst_1: Array<u8, L>,
-    dst_2: &'static str,
+    dst_2: &'static [u8],
 }
 
-impl<L: ArrayLength<u8>> Dst<L> {
+impl<L: ArraySize> Dst<L> {
-    pub(crate) fn new<CS: CipherSuite, T, TL: ArrayLength<u8>>(par_1: T, mode: Mode) -> Self
+    pub(crate) fn new<CS, TL>(par_1: Array<u8, TL>, mode: Mode) -> Self
     where
-        T: Into<GenericArray<u8, TL>>,
+        CS: CipherSuite,
-        TL: Add<U9, Output = L>,
+        TL: ArraySize + Add<U9, Output = L>,
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
     {
-        let par_1 = par_1.into();
         // Generates the contextString parameter as defined in
-        // <https://datatracker.ietf.org/doc/draft-irtf-cfrg-voprf/>
+        // <https://www.rfc-editor.org/rfc/rfc9497#section-3.1>
-        let par_2 = GenericArray::from(STR_OPRF)
+        let par_2 = ArrayN::<u8, 7>::from(STR_OPRF)
-            .concat([mode.to_u8()].into())
+            .concat(ArrayN::<u8, 1>::from([mode.to_u8()]))
-            .concat([b'-'].into());
+            .concat(ArrayN::<u8, 1>::from([b'-']));
 
         let dst_1 = par_1.concat(par_2);
         let dst_2 = CS::ID;
@@ -530,7 +479,7 @@ impl<L: ArrayLength<u8>> Dst<L> {
     }
 
     pub(crate) fn as_dst(&self) -> [&[u8]; 2] {
-        [&self.dst_1, self.dst_2.as_bytes()]
+        [&self.dst_1, self.dst_2]
     }
 
     pub(crate) fn i2osp_2(&self) -> [u8; 2] {
@@ -568,8 +517,6 @@ pub(crate) fn i2osp_2(input: usize) -> Result<[u8; 2], InternalError> {
         .map_err(|_| InternalError::I2osp)
 }
 
-pub(crate) fn i2osp_2_array<L: ArrayLength<u8> + IsLess<U256>>(
+pub(crate) fn i2osp_2_array<L: ArraySize + IsLess<U256>>() -> Array<u8, U2> {
-    _: &GenericArray<u8, L>,
-) -> GenericArray<u8, U2> {
     L::U16.to_be_bytes().into()
 }

src/error.rs

@@ -1,19 +1,14 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Errors which are produced during an execution of the protocol
 
-use displaydoc::Display;
-
 /// [`Result`](core::result::Result) shorthand that uses [`Error`].
 pub type Result<T, E = Error> = core::result::Result<T, E>;
 
 /// Represents an error in the manipulation of internal cryptographic data
-#[derive(Clone, Copy, Debug, Display, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[derive(Clone, Copy, Debug, displaydoc::Display, Eq, Hash, Ord, PartialEq, PartialOrd)]
 pub enum Error {
     /// Size of info is longer then [`u16::MAX`].
     Info,
@@ -29,6 +24,8 @@ pub enum Error {
     ProofVerification,
     /// The protocol has failed and can't be completed.
     Protocol,
+    /// Random number generator failure.
+    Rng,
 }
 
 /// Only used to implement [`Group`](crate::Group).
@@ -40,5 +37,4 @@ pub enum InternalError {
     I2osp,
 }
 
-#[cfg(feature = "std")]
+impl core::error::Error for Error {}
-impl std::error::Error for Error {}

src/group/elliptic_curve.rs

@@ -1,58 +1,73 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
-use digest::core_api::BlockSizeUser;
+use core::ops::{Add, Mul};
+use digest::block_api::BlockSizeUser;
+use digest::typenum::{IsLess, IsLessOrEqual, U256};
 use digest::{FixedOutput, HashMarker};
 use elliptic_curve::group::cofactor::CofactorGroup;
-use elliptic_curve::hash2curve::{ExpandMsgXmd, FromOkm, GroupDigest};
+use elliptic_curve::sec1::{FromSec1Point, ModulusSize, ToSec1Point};
-use elliptic_curve::sec1::{FromEncodedPoint, ModulusSize, ToEncodedPoint};
 use elliptic_curve::{
-    AffinePoint, Field, FieldBytesSize, Group as _, ProjectivePoint, PublicKey, Scalar, SecretKey,
+    AffinePoint, Field, FieldBytes, FieldBytesSize, Group as _, ProjectivePoint, PublicKey, Scalar,
+    SecretKey,
 };
-use generic_array::typenum::{IsLess, IsLessOrEqual, U256};
+use hash2curve::{ExpandMsgXmd, GroupDigest, MapToCurve, hash_to_scalar};
-use generic_array::GenericArray;
+use hybrid_array::typenum::{IsGreaterOrEqual, Prod, Sum, True, U2};
-use rand_core::{CryptoRng, RngCore};
+use hybrid_array::{Array, ArraySize};
+use rand_core::TryCryptoRng;
 
 use super::Group;
 use crate::{Error, InternalError, Result};
 
+type ElemLen<C> = <ScalarLen<C> as ModulusSize>::CompressedPointSize;
+type ScalarLen<C> = FieldBytesSize<C>;
+
 impl<C> Group for C
 where
     C: GroupDigest,
-    ProjectivePoint<Self>: CofactorGroup + ToEncodedPoint<Self>,
+    C::SecurityLevel: Mul<U2>,
-    FieldBytesSize<Self>: ModulusSize,
+    C::SecurityLevel: ArraySize,
-    AffinePoint<Self>: FromEncodedPoint<Self> + ToEncodedPoint<Self>,
+    <C::SecurityLevel as Mul<U2>>::Output: ArraySize,
-    Scalar<Self>: FromOkm,
+    ProjectivePoint<Self>: CofactorGroup + ToSec1Point<Self>,
+    ScalarLen<Self>: ModulusSize,
+    ScalarLen<Self>: ArraySize,
+    ScalarLen<Self>: hybrid_array::typenum::NonZero,
+    Scalar<Self>: elliptic_curve::ops::Reduce<Array<u8, <C as MapToCurve>::Length>>,
+    AffinePoint<Self>: FromSec1Point<Self> + ToSec1Point<Self>,
+    // `VoprfClientLen`, `PoprfClientLen`, `VoprfServerLen`, `PoprfServerLen`
+    ScalarLen<Self>: Add<ElemLen<Self>>,
+    Sum<ScalarLen<Self>, ElemLen<Self>>: ArraySize,
+    // `ProofLen`
+    ScalarLen<Self>: Add<ScalarLen<Self>>,
+    Sum<ScalarLen<Self>, ScalarLen<Self>>: ArraySize,
+    ElemLen<Self>: ArraySize,
 {
     type Elem = ProjectivePoint<Self>;
 
-    type ElemLen = <FieldBytesSize<Self> as ModulusSize>::CompressedPointSize;
+    type ElemLen = ElemLen<Self>;
 
     type Scalar = Scalar<Self>;
 
-    type ScalarLen = FieldBytesSize<Self>;
+    type ScalarLen = ScalarLen<Self>;
+
+    type SecurityLevel = C::SecurityLevel;
 
     // Implements the `hash_to_curve()` function from
-    // https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-hash-to-curve-11#section-3
+    // https://www.rfc-editor.org/rfc/rfc9380.html#section-3
-    fn hash_to_curve<H>(input: &[&[u8]], dst: &[&[u8]]) -> Result<Self::Elem, InternalError>
+    fn hash_to_curve<H>(input: &[&[u8]], dst: &[&[u8]]) -> Result<Self::Elem, InternalError> {
-    where
+        Self::hash_from_bytes(input, dst).map_err(|_| InternalError::Input)
-        H: BlockSizeUser + Default + FixedOutput + HashMarker,
-        H::OutputSize: IsLess<U256> + IsLessOrEqual<H::BlockSize>,
-    {
-        Self::hash_from_bytes::<ExpandMsgXmd<H>>(input, dst).map_err(|_| InternalError::Input)
     }
 
     // Implements the `HashToScalar()` function
     fn hash_to_scalar<H>(input: &[&[u8]], dst: &[&[u8]]) -> Result<Self::Scalar, InternalError>
     where
         H: BlockSizeUser + Default + FixedOutput + HashMarker,
-        H::OutputSize: IsLess<U256> + IsLessOrEqual<H::BlockSize>,
+        H::OutputSize: IsLess<U256>
+            + IsLessOrEqual<H::BlockSize, Output = True>
+            + IsGreaterOrEqual<Prod<C::SecurityLevel, U2>, Output = True>,
     {
-        <Self as GroupDigest>::hash_to_scalar::<ExpandMsgXmd<H>>(input, dst)
+        hash_to_scalar::<C, ExpandMsgXmd<H>, <C as MapToCurve>::Length>(input, dst)
             .map_err(|_| InternalError::Input)
     }
 
@@ -64,10 +79,10 @@ where
         ProjectivePoint::<Self>::identity()
     }
 
-    fn serialize_elem(elem: Self::Elem) -> GenericArray<u8, Self::ElemLen> {
+    fn serialize_elem(elem: Self::Elem) -> Array<u8, Self::ElemLen> {
-        let bytes = elem.to_encoded_point(true);
+        let bytes = elem.to_sec1_point(true);
         let bytes = bytes.as_bytes();
-        let mut result = GenericArray::default();
+        let mut result = Array::default();
         result[..bytes.len()].copy_from_slice(bytes);
         result
     }
@@ -78,8 +93,16 @@ where
             .map_err(|_| Error::Deserialization)
     }
 
-    fn random_scalar<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar {
+    fn random_scalar<R: TryCryptoRng>(rng: &mut R) -> Result<Self::Scalar> {
-        *SecretKey::<Self>::random(rng).to_nonzero_scalar()
+        loop {
+            let mut bytes = FieldBytes::<Self>::default();
+
+            rng.try_fill_bytes(&mut bytes).map_err(|_| Error::Rng)?;
+
+            if let Ok(key) = SecretKey::<Self>::from_slice(&bytes) {
+                return Ok(*key.to_nonzero_scalar());
+            }
+        }
     }
 
     fn invert_scalar(scalar: Self::Scalar) -> Self::Scalar {
@@ -95,8 +118,11 @@ where
         Scalar::<Self>::ZERO
     }
 
-    fn serialize_scalar(scalar: Self::Scalar) -> GenericArray<u8, Self::ScalarLen> {
+    fn serialize_scalar(scalar: Self::Scalar) -> Array<u8, Self::ScalarLen> {
-        scalar.into()
+        let bytes: FieldBytes<Self> = scalar.into();
+        let mut result = Array::<u8, Self::ScalarLen>::default();
+        result.as_mut_slice().copy_from_slice(bytes.as_ref());
+        result
     }
 
     fn deserialize_scalar(scalar_bits: &[u8]) -> Result<Self::Scalar> {

src/group/mod.rs

@@ -1,9 +1,6 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Defines the Group trait to specify the underlying prime order group
 
@@ -13,11 +10,11 @@ mod ristretto;
 
 use core::ops::{Add, Mul, Sub};
 
-use digest::core_api::BlockSizeUser;
+use digest::block_api::BlockSizeUser;
 use digest::{FixedOutput, HashMarker};
-use generic_array::typenum::{IsLess, IsLessOrEqual, U256};
+use hybrid_array::typenum::{IsGreaterOrEqual, IsLess, IsLessOrEqual, Prod, Sum, True, U2, U256};
-use generic_array::{ArrayLength, GenericArray};
+use hybrid_array::{Array, ArraySize};
-use rand_core::{CryptoRng, RngCore};
+use rand_core::{TryCryptoRng, TryRng};
 #[cfg(feature = "ristretto255")]
 pub use ristretto::Ristretto255;
 use subtle::{Choice, ConstantTimeEq};
@@ -26,8 +23,16 @@ use zeroize::Zeroize;
 use crate::{InternalError, Result};
 
 /// A prime-order subgroup of a base field (EC, prime-order field ...). This
-/// subgroup is noted additively — as in the draft RFC — in this trait.
+/// subgroup is noted additively — as in the RFC — in this trait.
-pub trait Group {
+pub trait Group
+where
+    // `VoprfClientLen`, `PoprfClientLen`, `VoprfServerLen`, `PoprfServerLen`
+    Self::ScalarLen: Add<Self::ElemLen>,
+    Sum<Self::ScalarLen, Self::ElemLen>: ArraySize,
+    // `ProofLen`
+    Self::ScalarLen: Add<Self::ScalarLen>,
+    Sum<Self::ScalarLen, Self::ScalarLen>: ArraySize,
+{
     /// The type of group elements
     type Elem: ConstantTimeEq
         + Copy
@@ -36,7 +41,7 @@ pub trait Group {
         + for<'a> Mul<&'a Self::Scalar, Output = Self::Elem>;
 
     /// The byte length necessary to represent group elements
-    type ElemLen: ArrayLength<u8> + 'static;
+    type ElemLen: ArraySize + 'static;
 
     /// The type of base field scalars
     type Scalar: ConstantTimeEq
@@ -47,7 +52,15 @@ pub trait Group {
         + for<'a> Sub<&'a Self::Scalar, Output = Self::Scalar>;
 
     /// The byte length necessary to represent scalars
-    type ScalarLen: ArrayLength<u8> + 'static;
+    type ScalarLen: ArraySize + 'static;
+
+    /// Security parameter `k` in bytes (i.e. `k / 8`), as defined in
+    /// [RFC 9380 §8](https://www.rfc-editor.org/rfc/rfc9380#section-8).
+    ///
+    /// Used to enforce `H::OutputSize >= 2 * SecurityLevel` in
+    /// `hash_to_curve` and `hash_to_scalar`, which corresponds to the
+    /// `expand_message` requirement `len_in_bytes = 2 * k / 8`.
+    type SecurityLevel: ArraySize + Mul<U2>;
 
     /// Transforms a password and domain separation tag (DST) into a curve point
     ///
@@ -57,7 +70,9 @@ pub trait Group {
     fn hash_to_curve<H>(input: &[&[u8]], dst: &[&[u8]]) -> Result<Self::Elem, InternalError>
     where
         H: BlockSizeUser + Default + FixedOutput + HashMarker,
-        H::OutputSize: IsLess<U256> + IsLessOrEqual<H::BlockSize>;
+        H::OutputSize: IsLess<U256>
+            + IsLessOrEqual<H::BlockSize, Output = True>
+            + IsGreaterOrEqual<Prod<Self::SecurityLevel, U2>, Output = True>;
 
     /// Hashes a slice of pseudo-random bytes to a scalar
     ///
@@ -67,7 +82,9 @@ pub trait Group {
     fn hash_to_scalar<H>(input: &[&[u8]], dst: &[&[u8]]) -> Result<Self::Scalar, InternalError>
     where
         H: BlockSizeUser + Default + FixedOutput + HashMarker,
-        H::OutputSize: IsLess<U256> + IsLessOrEqual<H::BlockSize>;
+        H::OutputSize: IsLess<U256>
+            + IsLessOrEqual<H::BlockSize, Output = True>
+            + IsGreaterOrEqual<Prod<Self::SecurityLevel, U2>, Output = True>;
 
     /// Get the base point for the group
     fn base_elem() -> Self::Elem;
@@ -81,7 +98,7 @@ pub trait Group {
     }
 
     /// Serializes the `self` group element
-    fn serialize_elem(elem: Self::Elem) -> GenericArray<u8, Self::ElemLen>;
+    fn serialize_elem(elem: Self::Elem) -> Array<u8, Self::ElemLen>;
 
     /// Return an element from its fixed-length bytes representation. If the
     /// element is the identity element, return an error.
@@ -91,8 +108,11 @@ pub trait Group {
     /// is not a valid point on the group or the identity element.
     fn deserialize_elem(element_bits: &[u8]) -> Result<Self::Elem>;
 
-    /// picks a scalar at random
+    /// Picks a scalar at random.
-    fn random_scalar<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar;
+    ///
+    /// # Errors
+    /// [`Error::Rng`](crate::Error::Rng) if the random number generator fails.
+    fn random_scalar<R: TryRng + TryCryptoRng>(rng: &mut R) -> Result<Self::Scalar>;
 
     /// The multiplicative inverse of this scalar
     fn invert_scalar(scalar: Self::Scalar) -> Self::Scalar;
@@ -105,7 +125,7 @@ pub trait Group {
     fn zero_scalar() -> Self::Scalar;
 
     /// Serializes a scalar to bytes
-    fn serialize_scalar(scalar: Self::Scalar) -> GenericArray<u8, Self::ScalarLen>;
+    fn serialize_scalar(scalar: Self::Scalar) -> Array<u8, Self::ScalarLen>;
 
     /// Return a scalar from its fixed-length bytes representation. If the
     /// scalar is zero or invalid, then return an error.

src/group/ristretto.rs

@@ -1,20 +1,21 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
+
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+use core::num::NonZeroU16;
-// of this source tree.
 
 use curve25519_dalek::constants::RISTRETTO_BASEPOINT_POINT;
 use curve25519_dalek::ristretto::{CompressedRistretto, RistrettoPoint};
 use curve25519_dalek::scalar::Scalar;
 use curve25519_dalek::traits::Identity;
-use digest::core_api::BlockSizeUser;
+use digest::block_api::BlockSizeUser;
 use digest::{FixedOutput, HashMarker};
-use elliptic_curve::hash2curve::{ExpandMsg, ExpandMsgXmd, Expander};
+use hash2curve::{ExpandMsg, ExpandMsgXmd, Expander};
-use generic_array::typenum::{IsLess, IsLessOrEqual, U256, U32, U64};
+use hybrid_array::Array;
-use generic_array::GenericArray;
+use hybrid_array::typenum::{
-use rand_core::{CryptoRng, RngCore};
+    IsGreaterOrEqual, IsLess, IsLessOrEqual, Prod, True, U2, U16, U32, U256,
+};
+use rand_core::{TryCryptoRng, TryRng};
 use subtle::ConstantTimeEq;
 
 use super::Group;
@@ -26,7 +27,7 @@ pub struct Ristretto255;
 
 #[cfg(feature = "ristretto255-ciphersuite")]
 impl crate::CipherSuite for Ristretto255 {
-    const ID: &'static str = "ristretto255-SHA512";
+    const ID: &'static [u8] = b"ristretto255-SHA512";
 
     type Group = Ristretto255;
 
@@ -42,34 +43,52 @@ impl Group for Ristretto255 {
 
     type ScalarLen = U32;
 
+    type SecurityLevel = U16;
+
     // Implements the `hash_to_ristretto255()` function from
-    // https://www.ietf.org/archive/id/draft-irtf-cfrg-hash-to-curve-10.txt
+    // https://www.rfc-editor.org/rfc/rfc9380.html#appendix-B
     fn hash_to_curve<H>(input: &[&[u8]], dst: &[&[u8]]) -> Result<Self::Elem, InternalError>
     where
         H: BlockSizeUser + Default + FixedOutput + HashMarker,
-        H::OutputSize: IsLess<U256> + IsLessOrEqual<H::BlockSize>,
+        H::OutputSize: IsLess<U256>
+            + IsLessOrEqual<H::BlockSize, Output = True>
+            + IsGreaterOrEqual<Prod<Self::SecurityLevel, U2>, Output = True>,
     {
-        let mut uniform_bytes = GenericArray::<_, U64>::default();
+        let mut uniform_bytes = [0u8; 64];
-        ExpandMsgXmd::<H>::expand_message(input, dst, 64)
-            .map_err(|_| InternalError::Input)?
-            .fill_bytes(&mut uniform_bytes);
 
-        Ok(RistrettoPoint::from_uniform_bytes(&uniform_bytes.into()))
+        <ExpandMsgXmd<H> as ExpandMsg<U16>>::expand_message(
+            input,
+            dst,
+            NonZeroU16::new(64).unwrap(),
+        )
+        .map_err(|_| InternalError::Input)?
+        .fill_bytes(&mut uniform_bytes)
+        .map_err(|_| InternalError::Input)?;
+
+        Ok(RistrettoPoint::from_uniform_bytes(&uniform_bytes))
     }
 
     // Implements the `HashToScalar()` function from
-    // https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-07.html#section-4.1
+    // https://www.rfc-editor.org/rfc/rfc9497#section-4.1
     fn hash_to_scalar<H>(input: &[&[u8]], dst: &[&[u8]]) -> Result<Self::Scalar, InternalError>
     where
         H: BlockSizeUser + Default + FixedOutput + HashMarker,
-        H::OutputSize: IsLess<U256> + IsLessOrEqual<H::BlockSize>,
+        H::OutputSize: IsLess<U256>
+            + IsLessOrEqual<H::BlockSize, Output = True>
+            + IsGreaterOrEqual<Prod<Self::SecurityLevel, U2>, Output = True>,
     {
-        let mut uniform_bytes = GenericArray::<_, U64>::default();
+        let mut uniform_bytes = [0u8; 64];
-        ExpandMsgXmd::<H>::expand_message(input, dst, 64)
-            .map_err(|_| InternalError::Input)?
-            .fill_bytes(&mut uniform_bytes);
 
-        Ok(Scalar::from_bytes_mod_order_wide(&uniform_bytes.into()))
+        <ExpandMsgXmd<H> as ExpandMsg<U16>>::expand_message(
+            input,
+            dst,
+            NonZeroU16::new(64).unwrap(),
+        )
+        .map_err(|_| InternalError::Input)?
+        .fill_bytes(&mut uniform_bytes)
+        .map_err(|_| InternalError::Input)?;
+
+        Ok(Scalar::from_bytes_mod_order_wide(&uniform_bytes))
     }
 
     fn base_elem() -> Self::Elem {
@@ -81,7 +100,7 @@ impl Group for Ristretto255 {
     }
 
     // serialization of a group element
-    fn serialize_elem(elem: Self::Elem) -> GenericArray<u8, Self::ElemLen> {
+    fn serialize_elem(elem: Self::Elem) -> Array<u8, Self::ElemLen> {
         elem.compress().to_bytes().into()
     }
 
@@ -93,12 +112,14 @@ impl Group for Ristretto255 {
             .ok_or(Error::Deserialization)
     }
 
-    fn random_scalar<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar {
+    fn random_scalar<R: TryRng + TryCryptoRng>(rng: &mut R) -> Result<Self::Scalar> {
         loop {
-            let scalar = Scalar::random(rng);
+            let mut scalar_bytes = [0u8; 32];
+            rng.try_fill_bytes(&mut scalar_bytes)
+                .map_err(|_| Error::Rng)?;
 
-            if scalar != Scalar::ZERO {
+            if let Ok(scalar) = Self::deserialize_scalar(&scalar_bytes) {
-                break scalar;
+                break Ok(scalar);
             }
         }
     }
@@ -116,7 +137,7 @@ impl Group for Ristretto255 {
         Scalar::ZERO
     }
 
-    fn serialize_scalar(scalar: Self::Scalar) -> GenericArray<u8, Self::ScalarLen> {
+    fn serialize_scalar(scalar: Self::Scalar) -> Array<u8, Self::ScalarLen> {
         scalar.to_bytes().into()
     }
 

src/group/tests.rs

@@ -1,9 +1,6 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Includes a series of tests for the group implementations
 
@@ -16,6 +13,7 @@ use crate::{Error, Group, Result};
 fn test_group_properties() -> Result<()> {
     use p256::NistP256;
     use p384::NistP384;
+    use p521::NistP521;
 
     #[cfg(feature = "ristretto255")]
     {
@@ -31,6 +29,9 @@ fn test_group_properties() -> Result<()> {
     test_identity_element_error::<NistP384>()?;
     test_zero_scalar_error::<NistP384>()?;
 
+    test_identity_element_error::<NistP521>()?;
+    test_zero_scalar_error::<NistP521>()?;
+
     Ok(())
 }
 

src/lib.rs

@@ -1,16 +1,11 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! An implementation of a verifiable oblivious pseudorandom function (VOPRF)
 //!
 //! Note: This implementation is in sync with
-//! [draft-irtf-cfrg-voprf-19](https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-19.html),
+//! [RFC 9497](https://www.rfc-editor.org/rfc/rfc9497).
-//! but this specification is subject to change, until the final version
-//! published by the IETF.
 //!
 //! # Overview
 //!
@@ -21,7 +16,7 @@
 //! We will use the following choice in this example:
 //!
 //! ```ignore
-//! type CipherSuite = voprf::Ristretto255;
+//! type CipherSuite = voprf_vx::Ristretto255;
 //! ```
 //!
 //! ## Modes of Operation
@@ -52,14 +47,14 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! use rand::rngs::OsRng;
+//! use rand::rngs::SysRng;
-//! use rand::RngCore;
+//! use rand::Rng;
-//! use voprf::OprfServer;
+//! use voprf_vx::OprfServer;
 //!
-//! let mut server_rng = OsRng;
+//! let mut server_rng = SysRng;
 //! let server = OprfServer::<CipherSuite>::new(&mut server_rng);
 //! ```
 //!
@@ -72,14 +67,14 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! use rand::rngs::OsRng;
+//! use rand::rngs::SysRng;
-//! use rand::RngCore;
+//! use rand::Rng;
-//! use voprf::OprfClient;
+//! use voprf_vx::OprfClient;
 //!
-//! let mut client_rng = OsRng;
+//! let mut client_rng = SysRng;
 //! let client_blind_result = OprfClient::<CipherSuite>::blind(b"input", &mut client_rng)
 //!     .expect("Unable to construct client");
 //! ```
@@ -93,19 +88,19 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::OprfClient;
+//! # use voprf_vx::OprfClient;
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let client_blind_result = OprfClient::<CipherSuite>::blind(
 //! #     b"input",
 //! #     &mut client_rng,
 //! # ).expect("Unable to construct client");
-//! # use voprf::OprfServer;
+//! # use voprf_vx::OprfServer;
-//! # let mut server_rng = OsRng;
+//! # let mut server_rng = SysRng;
 //! # let server = OprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! let server_evaluate_result = server.blind_evaluate(&client_blind_result.message);
 //! ```
@@ -118,19 +113,19 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::OprfClient;
+//! # use voprf_vx::OprfClient;
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let client_blind_result = OprfClient::<CipherSuite>::blind(
 //! #     b"input",
 //! #     &mut client_rng,
 //! # ).expect("Unable to construct client");
-//! # use voprf::OprfServer;
+//! # use voprf_vx::OprfServer;
-//! # let mut server_rng = OsRng;
+//! # let mut server_rng = SysRng;
 //! # let server = OprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! # let message = server.blind_evaluate(&client_blind_result.message);
 //! let client_finalize_result = client_blind_result
@@ -151,19 +146,19 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::OprfClient;
+//! # use voprf_vx::OprfClient;
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let client_blind_result = OprfClient::<CipherSuite>::blind(
 //! #     b"input",
 //! #     &mut client_rng,
 //! # ).expect("Unable to construct client");
-//! # use voprf::OprfServer;
+//! # use voprf_vx::OprfServer;
-//! # let mut server_rng = OsRng;
+//! # let mut server_rng = SysRng;
 //! # let server = OprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! # let message = server.blind_evaluate(&client_blind_result.message);
 //! let client_finalize_result = client_blind_result
@@ -198,14 +193,14 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! use rand::rngs::OsRng;
+//! use rand::rngs::SysRng;
-//! use rand::RngCore;
+//! use rand::Rng;
-//! use voprf::VoprfServer;
+//! use voprf_vx::VoprfServer;
 //!
-//! let mut server_rng = OsRng;
+//! let mut server_rng = SysRng;
 //! let server = VoprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //!
 //! // To be sent to the client
@@ -225,14 +220,14 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! use rand::rngs::OsRng;
+//! use rand::rngs::SysRng;
-//! use rand::RngCore;
+//! use rand::Rng;
-//! use voprf::VoprfClient;
+//! use voprf_vx::VoprfClient;
 //!
-//! let mut client_rng = OsRng;
+//! let mut client_rng = SysRng;
 //! let client_blind_result = VoprfClient::<CipherSuite>::blind(b"input", &mut client_rng)
 //!     .expect("Unable to construct client");
 //! ```
@@ -247,19 +242,19 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::{VoprfServerEvaluateResult, VoprfClient};
+//! # use voprf_vx::{VoprfServerEvaluateResult, VoprfClient};
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let client_blind_result = VoprfClient::<CipherSuite>::blind(
 //! #     b"input",
 //! #     &mut client_rng,
 //! # ).expect("Unable to construct client");
-//! # use voprf::VoprfServer;
+//! # use voprf_vx::VoprfServer;
-//! # let mut server_rng = OsRng;
+//! # let mut server_rng = SysRng;
 //! # let server = VoprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! let VoprfServerEvaluateResult { message, proof } =
 //!     server.blind_evaluate(&mut server_rng, &client_blind_result.message);
@@ -274,19 +269,19 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::VoprfClient;
+//! # use voprf_vx::VoprfClient;
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let client_blind_result = VoprfClient::<CipherSuite>::blind(
 //! #     b"input",
 //! #     &mut client_rng,
 //! # ).expect("Unable to construct client");
-//! # use voprf::VoprfServer;
+//! # use voprf_vx::VoprfServer;
-//! # let mut server_rng = OsRng;
+//! # let mut server_rng = SysRng;
 //! # let server = VoprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! # let server_evaluate_result = server.blind_evaluate(
 //! #     &mut server_rng,
@@ -315,19 +310,19 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::VoprfClient;
+//! # use voprf_vx::VoprfClient;
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let client_blind_result = VoprfClient::<CipherSuite>::blind(
 //! #     b"input",
 //! #     &mut client_rng,
 //! # ).expect("Unable to construct client");
-//! # use voprf::VoprfServer;
+//! # use voprf_vx::VoprfServer;
-//! # let mut server_rng = OsRng;
+//! # let mut server_rng = SysRng;
 //! # let server = VoprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! # let server_evaluate_result = server.blind_evaluate(
 //! #     &mut server_rng,
@@ -369,13 +364,13 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::VoprfClient;
+//! # use voprf_vx::VoprfClient;
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! let mut client_rng = OsRng;
+//! let mut client_rng = SysRng;
 //! let mut client_states = vec![];
 //! let mut client_messages = vec![];
 //! for _ in 0..10 {
@@ -393,13 +388,13 @@
 //!
 //! ```
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::{VoprfServerBatchEvaluateFinishResult, VoprfClient};
+//! # use voprf_vx::{VoprfServerBatchEvaluateFinishResult, VoprfClient};
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let mut client_states = vec![];
 //! # let mut client_messages = vec![];
 //! # for _ in 0..10 {
@@ -410,8 +405,8 @@
 //! #     client_states.push(client_blind_result.state);
 //! #     client_messages.push(client_blind_result.message);
 //! # }
-//! # use voprf::VoprfServer;
+//! # use voprf_vx::VoprfServer;
-//! let mut server_rng = OsRng;
+//! let mut server_rng = SysRng;
 //! # let server = VoprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! let prepared_evaluation_elements = server.batch_blind_evaluate_prepare(client_messages.iter());
 //! let prepared_elements: Vec<_> = prepared_evaluation_elements.collect();
@@ -427,13 +422,13 @@
 //! ```
 //! # #[cfg(feature = "alloc")] {
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::{VoprfServerBatchEvaluateResult, VoprfClient};
+//! # use voprf_vx::{VoprfServerBatchEvaluateResult, VoprfClient};
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let mut client_states = vec![];
 //! # let mut client_messages = vec![];
 //! # for _ in 0..10 {
@@ -444,8 +439,8 @@
 //! #     client_states.push(client_blind_result.state);
 //! #     client_messages.push(client_blind_result.message);
 //! # }
-//! # use voprf::VoprfServer;
+//! # use voprf_vx::VoprfServer;
-//! let mut server_rng = OsRng;
+//! let mut server_rng = SysRng;
 //! # let server = VoprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! let VoprfServerBatchEvaluateResult { messages, proof } = server
 //!     .batch_blind_evaluate(&mut server_rng, &client_messages)
@@ -461,13 +456,13 @@
 //! ```
 //! # #[cfg(feature = "alloc")] {
 //! # #[cfg(feature = "ristretto255")]
-//! # type CipherSuite = voprf::Ristretto255;
+//! # type CipherSuite = voprf_vx::Ristretto255;
 //! # #[cfg(not(feature = "ristretto255"))]
 //! # type CipherSuite = p256::NistP256;
-//! # use voprf::{VoprfServerBatchEvaluateResult, VoprfClient};
+//! # use voprf_vx::{VoprfServerBatchEvaluateResult, VoprfClient};
-//! # use rand::{rngs::OsRng, RngCore};
+//! # use rand::{rngs::SysRng, Rng};
 //! #
-//! # let mut client_rng = OsRng;
+//! # let mut client_rng = SysRng;
 //! # let mut client_states = vec![];
 //! # let mut client_messages = vec![];
 //! # for _ in 0..10 {
@@ -478,8 +473,8 @@
 //! #     client_states.push(client_blind_result.state);
 //! #     client_messages.push(client_blind_result.message);
 //! # }
-//! # use voprf::VoprfServer;
+//! # use voprf_vx::VoprfServer;
-//! # let mut server_rng = OsRng;
+//! # let mut server_rng = SysRng;
 //! # let server = VoprfServer::<CipherSuite>::new(&mut server_rng).unwrap();
 //! # let VoprfServerBatchEvaluateResult { messages, proof } = server
 //! #     .batch_blind_evaluate(&mut server_rng, &client_messages)
@@ -511,7 +506,7 @@
 //! and [PoprfClient] are used, and that each of the functions accept an
 //! additional (and optional) info parameter which represents the public input.
 //! See
-//! <https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-11.html#name-poprf-public-input>
+//! <https://www.rfc-editor.org/rfc/rfc9497#name-poprf-public-input>
 //! for more detailed information on how this public input should be used.
 //!
 //! # Features
@@ -539,7 +534,7 @@
 //!     (https://docs.rs/curve25519-dalek/4.0.0-pre.5/curve25519_dalek/index.html#backends)
 
 #![no_std]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 #![cfg_attr(not(test), deny(unsafe_code))]
 #![warn(
     clippy::cargo,

src/oprf.rs

@@ -1,24 +1,20 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Contains the main OPRF API
 
 use core::iter::{self, Map};
 
 use derive_where::derive_where;
-use digest::core_api::BlockSizeUser;
+use digest::{Digest, Output};
-use digest::{Digest, Output, OutputSizeUser};
+use hybrid_array::Array;
-use generic_array::typenum::{IsLess, IsLessOrEqual, Unsigned, U256};
+use hybrid_array::typenum::Unsigned;
-use generic_array::GenericArray;
+use rand_core::{TryCryptoRng, TryRng};
-use rand_core::{CryptoRng, RngCore};
 
 use crate::common::{
-    derive_key_internal, deterministic_blind_unchecked, hash_to_group, i2osp_2,
+    BlindedElement, EvaluationElement, Mode, STR_FINALIZE, derive_key_internal,
-    server_evaluate_hash_input, BlindedElement, EvaluationElement, Mode, STR_FINALIZE,
+    deterministic_blind_unchecked, hash_to_group, i2osp_2, server_evaluate_hash_input,
 };
 #[cfg(feature = "serde")]
 use crate::serialization::serde::Scalar;
@@ -43,11 +39,7 @@ use crate::{CipherSuite, Error, Group, Result};
     derive(serde::Deserialize, serde::Serialize),
     serde(bound = "")
 )]
-pub struct OprfClient<CS: CipherSuite>
+pub struct OprfClient<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
     pub(crate) blind: <CS::Group as Group>::Scalar,
 }
@@ -61,11 +53,7 @@ where
     derive(serde::Deserialize, serde::Serialize),
     serde(bound = "")
 )]
-pub struct OprfServer<CS: CipherSuite>
+pub struct OprfServer<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
     pub(crate) sk: <CS::Group as Group>::Scalar,
 }
@@ -75,21 +63,17 @@ where
 // =================== //
 /////////////////////////
 
-impl<CS: CipherSuite> OprfClient<CS>
+impl<CS: CipherSuite> OprfClient<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Computes the first step for the multiplicative blinding version of
     /// DH-OPRF.
     ///
     /// # Errors
     /// [`Error::Input`] if the `input` is empty or longer then [`u16::MAX`].
-    pub fn blind<R: RngCore + CryptoRng>(
+    pub fn blind<R: TryRng + TryCryptoRng>(
         input: &[u8],
         blinding_factor_rng: &mut R,
     ) -> Result<OprfClientBlindResult<CS>> {
-        let blind = CS::Group::random_scalar(blinding_factor_rng);
+        let blind = CS::Group::random_scalar(blinding_factor_rng)?;
         Self::deterministic_blind_unchecked_inner(input, blind)
     }
 
@@ -153,18 +137,14 @@ where
     }
 }
 
-impl<CS: CipherSuite> OprfServer<CS>
+impl<CS: CipherSuite> OprfServer<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Produces a new instance of a [OprfServer] using a supplied RNG
     ///
     /// # Errors
     /// [`Error::Protocol`] if the protocol fails and can't be completed.
-    pub fn new<R: RngCore + CryptoRng>(rng: &mut R) -> Result<Self> {
+    pub fn new<R: TryRng + TryCryptoRng>(rng: &mut R) -> Result<Self> {
-        let mut seed = GenericArray::<_, <CS::Group as Group>::ScalarLen>::default();
+        let mut seed = Array::<_, <CS::Group as Group>::ScalarLen>::default();
-        rng.fill_bytes(&mut seed);
+        rng.try_fill_bytes(&mut seed).map_err(|_| Error::Protocol)?;
         Self::new_from_seed(&seed, &[])
     }
 
@@ -193,7 +173,7 @@ where
         Ok(Self { sk })
     }
 
-    // Only used for tests
+    /// Only used for tests
     #[cfg(test)]
     pub fn get_private_key(&self) -> <CS::Group as Group>::Scalar {
         self.sk
@@ -230,11 +210,7 @@ where
 
 /// Contains the fields that are returned by a non-verifiable client blind
 #[derive_where(Debug; <CS::Group as Group>::Scalar, <CS::Group as Group>::Elem)]
-pub struct OprfClientBlindResult<CS: CipherSuite>
+pub struct OprfClientBlindResult<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// The state to be persisted on the client
     pub state: OprfClient<CS>,
     /// The message to send to the server
@@ -260,11 +236,7 @@ fn finalize_after_unblind<
 >(
     inputs_and_unblinded_elements: IE,
     _unused: &'a [u8],
-) -> FinalizeAfterUnblindResult<CS, I, IE>
+) -> FinalizeAfterUnblindResult<'a, CS, I, IE> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     inputs_and_unblinded_elements.map(|(input, unblinded_element)| {
         let elem_len = <CS::Group as Group>::ElemLen::U16.to_be_bytes();
 
@@ -291,23 +263,20 @@ where
 mod tests {
     use core::ptr;
 
-    use rand::rngs::OsRng;
+    use rand::TryRng;
+    use rand::rngs::SysRng;
 
     use super::*;
-    use crate::common::{Dst, STR_HASH_TO_GROUP};
     use crate::Group;
+    use crate::common::{Dst, STR_HASH_TO_GROUP};
 
     fn prf<CS: CipherSuite>(
         input: &[u8],
         key: <CS::Group as Group>::Scalar,
         info: &[u8],
         mode: Mode,
-    ) -> Output<CS::Hash>
+    ) -> Output<CS::Hash> {
-    where
+        let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, mode);
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
-        let dst = Dst::new::<CS, _, _>(STR_HASH_TO_GROUP, mode);
         let point = CS::Group::hash_to_curve::<CS::Hash>(&[input], &dst.as_dst()).unwrap();
 
         let res = point * &key;
@@ -318,13 +287,9 @@ mod tests {
             .unwrap()
     }
 
-    fn base_retrieval<CS: CipherSuite>()
+    fn base_retrieval<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = OprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server = OprfServer::<CS>::new(&mut rng).unwrap();
         let message = server.blind_evaluate(&client_blind_result.message);
@@ -333,21 +298,17 @@ mod tests {
         assert_eq!(client_finalize_result, res2);
     }
 
-    fn base_inversion_unsalted<CS: CipherSuite>()
+    fn base_inversion_unsalted<CS: CipherSuite>() {
-    where
+        let mut rng = SysRng;
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
-        let mut rng = OsRng;
         let mut input = [0u8; 64];
-        rng.fill_bytes(&mut input);
+        rng.try_fill_bytes(&mut input).unwrap();
         let client_blind_result = OprfClient::<CS>::blind(&input, &mut rng).unwrap();
         let client_finalize_result = client_blind_result
             .state
             .finalize(&input, &EvaluationElement(client_blind_result.message.0))
             .unwrap();
 
-        let dst = Dst::new::<CS, _, _>(STR_HASH_TO_GROUP, Mode::Oprf);
+        let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, Mode::Oprf);
         let point = CS::Group::hash_to_curve::<CS::Hash>(&[&input], &dst.as_dst()).unwrap();
         let res2 = finalize_after_unblind::<CS, _, _>(iter::once((input.as_ref(), point)), &[])
             .next()
@@ -357,13 +318,9 @@ mod tests {
         assert_eq!(client_finalize_result, res2);
     }
 
-    fn server_evaluate<CS: CipherSuite>()
+    fn server_evaluate<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = OprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server = OprfServer::<CS>::new(&mut rng).unwrap();
         let server_result = server.blind_evaluate(&client_blind_result.message);
@@ -385,13 +342,9 @@ mod tests {
         assert!(client_finalize != server_evaluate);
     }
 
-    fn zeroize_oprf_client<CS: CipherSuite>()
+    fn zeroize_oprf_client<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = OprfClient::<CS>::blind(input, &mut rng).unwrap();
 
         let mut state = client_blind_result.state;
@@ -403,13 +356,9 @@ mod tests {
         assert!(message.serialize().iter().all(|&x| x == 0));
     }
 
-    fn zeroize_oprf_server<CS: CipherSuite>()
+    fn zeroize_oprf_server<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = OprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server = OprfServer::<CS>::new(&mut rng).unwrap();
         let mut message = server.blind_evaluate(&client_blind_result.message);
@@ -426,6 +375,7 @@ mod tests {
     fn test_functionality() -> Result<()> {
         use p256::NistP256;
         use p384::NistP384;
+        use p521::NistP521;
 
         #[cfg(feature = "ristretto255")]
         {
@@ -453,6 +403,13 @@ mod tests {
         zeroize_oprf_client::<NistP384>();
         zeroize_oprf_server::<NistP384>();
 
+        base_retrieval::<NistP521>();
+        base_inversion_unsalted::<NistP521>();
+        server_evaluate::<NistP521>();
+
+        zeroize_oprf_client::<NistP521>();
+        zeroize_oprf_server::<NistP521>();
+
         Ok(())
     }
 }

src/poprf.rs

@@ -1,9 +1,6 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Contains the main POPRF API
 
@@ -12,16 +9,15 @@ use alloc::vec::Vec;
 use core::iter::{self, Map, Repeat, Zip};
 
 use derive_where::derive_where;
-use digest::core_api::BlockSizeUser;
 use digest::{Digest, Output, OutputSizeUser};
-use generic_array::typenum::{IsLess, IsLessOrEqual, Unsigned, U256};
+use hybrid_array::typenum::Unsigned;
-use generic_array::GenericArray;
+use hybrid_array::{Array, ArraySize};
-use rand_core::{CryptoRng, RngCore};
+use rand_core::{TryCryptoRng, TryRng};
 
 use crate::common::{
-    derive_keypair, deterministic_blind_unchecked, generate_proof, hash_to_group, i2osp_2,
+    BlindedElement, Dst, EvaluationElement, Mode, PreparedEvaluationElement, Proof, STR_FINALIZE,
-    server_evaluate_hash_input, verify_proof, BlindedElement, Dst, EvaluationElement, Mode,
+    STR_HASH_TO_SCALAR, STR_INFO, derive_keypair, deterministic_blind_unchecked, generate_proof,
-    PreparedEvaluationElement, Proof, STR_FINALIZE, STR_HASH_TO_SCALAR, STR_INFO,
+    hash_to_group, i2osp_2, server_evaluate_hash_input, verify_proof,
 };
 #[cfg(feature = "serde")]
 use crate::serialization::serde::{Element, Scalar};
@@ -41,11 +37,7 @@ use crate::{CipherSuite, Error, Group, Result};
     derive(serde::Deserialize, serde::Serialize),
     serde(bound = "")
 )]
-pub struct PoprfClient<CS: CipherSuite>
+pub struct PoprfClient<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
     pub(crate) blind: <CS::Group as Group>::Scalar,
     #[cfg_attr(feature = "serde", serde(with = "Element::<CS::Group>"))]
@@ -61,11 +53,7 @@ where
     derive(serde::Deserialize, serde::Serialize),
     serde(bound = "")
 )]
-pub struct PoprfServer<CS: CipherSuite>
+pub struct PoprfServer<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
     pub(crate) sk: <CS::Group as Group>::Scalar,
     #[cfg_attr(feature = "serde", serde(with = "Element::<CS::Group>"))]
@@ -77,21 +65,17 @@ where
 // =================== //
 /////////////////////////
 
-impl<CS: CipherSuite> PoprfClient<CS>
+impl<CS: CipherSuite> PoprfClient<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Computes the first step for the multiplicative blinding version of
     /// DH-OPRF.
     ///
     /// # Errors
     /// [`Error::Input`] if the `input` is empty or longer than [`u16::MAX`].
-    pub fn blind<R: RngCore + CryptoRng>(
+    pub fn blind<R: TryRng + TryCryptoRng>(
         input: &[u8],
         blinding_factor_rng: &mut R,
     ) -> Result<PoprfClientBlindResult<CS>> {
-        let blind = CS::Group::random_scalar(blinding_factor_rng);
+        let blind = CS::Group::random_scalar(blinding_factor_rng)?;
         Self::deterministic_blind_unchecked_inner(input, blind)
     }
 
@@ -144,7 +128,10 @@ where
         proof: &Proof<CS>,
         pk: <CS::Group as Group>::Elem,
         info: Option<&[u8]>,
-    ) -> Result<Output<CS::Hash>> {
+    ) -> Result<Output<CS::Hash>>
+    where
+        <<CS as CipherSuite>::Hash as OutputSizeUser>::OutputSize: ArraySize,
+    {
         let clients = core::array::from_ref(self);
         let messages = core::array::from_ref(evaluation_element);
 
@@ -179,6 +166,7 @@ where
         <&'a IC as IntoIterator>::IntoIter: ExactSizeIterator,
         &'a IM: 'a + IntoIterator<Item = &'a EvaluationElement<CS>>,
         <&'a IM as IntoIterator>::IntoIter: ExactSizeIterator,
+        <<CS as CipherSuite>::Hash as OutputSizeUser>::OutputSize: ArraySize,
     {
         let unblinded_elements = poprf_unblind(clients, messages, pk, proof, info)?;
 
@@ -192,18 +180,14 @@ where
     }
 }
 
-impl<CS: CipherSuite> PoprfServer<CS>
+impl<CS: CipherSuite> PoprfServer<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Produces a new instance of a [PoprfServer] using a supplied RNG
     ///
     /// # Errors
     /// [`Error::Protocol`] if the protocol fails and can't be completed.
-    pub fn new<R: RngCore + CryptoRng>(rng: &mut R) -> Result<Self> {
+    pub fn new<R: TryRng + TryCryptoRng>(rng: &mut R) -> Result<Self> {
-        let mut seed = GenericArray::<_, <CS::Group as Group>::ScalarLen>::default();
+        let mut seed = Array::<_, <CS::Group as Group>::ScalarLen>::default();
-        rng.fill_bytes(&mut seed);
+        rng.try_fill_bytes(&mut seed).map_err(|_| Error::Protocol)?;
 
         Self::new_from_seed(&seed, &[])
     }
@@ -234,7 +218,7 @@ where
         Ok(Self { sk, pk })
     }
 
-    // Only used for tests
+    /// Only used for tests
     #[cfg(test)]
     pub fn get_private_key(&self) -> <CS::Group as Group>::Scalar {
         self.sk
@@ -247,7 +231,7 @@ where
     /// # Errors
     /// - [`Error::Info`] if the `info` is longer than `u16::MAX`.
     /// - [`Error::Protocol`] if the protocol fails and can't be completed.
-    pub fn blind_evaluate<R: RngCore + CryptoRng>(
+    pub fn blind_evaluate<R: TryRng + TryCryptoRng>(
         &self,
         rng: &mut R,
         blinded_element: &BlindedElement<CS>,
@@ -285,7 +269,7 @@ where
     /// - [`Error::Info`] if the `info` is longer than `u16::MAX`.
     /// - [`Error::Protocol`] if the protocol fails and can't be completed.
     #[cfg(feature = "alloc")]
-    pub fn batch_blind_evaluate<'a, R: RngCore + CryptoRng, IE>(
+    pub fn batch_blind_evaluate<'a, R: TryRng + TryCryptoRng, IE>(
         &self,
         rng: &mut R,
         blinded_elements: &'a IE,
@@ -358,7 +342,7 @@ where
     pub fn batch_blind_evaluate_finish<
         'a,
         'b,
-        R: RngCore + CryptoRng,
+        R: TryRng + TryCryptoRng,
         IB: Iterator<Item = &'a BlindedElement<CS>> + ExactSizeIterator,
         IE,
     >(
@@ -383,7 +367,7 @@ where
             tweaked_key,
             prepared_evaluation_elements
                 .into_iter()
-                .map(|element| element.0 .0),
+                .map(|element| element.0.0),
             blinded_elements.map(|element| element.0),
             Mode::Poprf,
         )?;
@@ -391,7 +375,7 @@ where
         let messages = prepared_evaluation_elements.into_iter().map(<fn(
             &PreparedEvaluationElement<CS>,
         ) -> _>::from(
-            |element| EvaluationElement(element.0 .0),
+            |element| EvaluationElement(element.0.0),
         ));
 
         Ok(PoprfServerBatchEvaluateFinishResult { messages, proof })
@@ -426,11 +410,7 @@ where
     }
 }
 
-impl<CS: CipherSuite> BlindedElement<CS>
+impl<CS: CipherSuite> BlindedElement<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Creates a [BlindedElement] from a raw group element.
     ///
     /// # Caution
@@ -449,11 +429,7 @@ where
     }
 }
 
-impl<CS: CipherSuite> EvaluationElement<CS>
+impl<CS: CipherSuite> EvaluationElement<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Creates an [EvaluationElement] from a raw group element.
     ///
     /// # Caution
@@ -479,11 +455,7 @@ where
 
 /// Contains the fields that are returned by a verifiable client blind
 #[derive_where(Debug; <CS::Group as Group>::Scalar, <CS::Group as Group>::Elem)]
-pub struct PoprfClientBlindResult<CS: CipherSuite>
+pub struct PoprfClientBlindResult<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// The state to be persisted on the client
     pub state: PoprfClient<CS>,
     /// The message to send to the server
@@ -496,11 +468,7 @@ pub type PoprfClientBatchFinalizeResult<'a, CS, II, IC, IM> =
 
 /// Contains the fields that are returned by a verifiable server evaluate
 #[derive_where(Debug; <CS::Group as Group>::Scalar, <CS::Group as Group>::Elem)]
-pub struct PoprfServerEvaluateResult<CS: CipherSuite>
+pub struct PoprfServerEvaluateResult<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// The message to send to the client
     pub message: EvaluationElement<CS>,
     /// The proof for the client to verify
@@ -510,11 +478,7 @@ where
 /// Contains the fields that are returned by a verifiable server batch evaluate
 #[derive_where(Debug; <CS::Group as Group>::Scalar, <CS::Group as Group>::Elem)]
 #[cfg(feature = "alloc")]
-pub struct PoprfServerBatchEvaluateResult<CS: CipherSuite>
+pub struct PoprfServerBatchEvaluateResult<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// The messages to send to the client
     pub messages: Vec<EvaluationElement<CS>>,
     /// The proof for the client to verify
@@ -544,19 +508,12 @@ pub type PoprfServerBatchEvaluatePreparedEvaluationElements<CS, I> = Map<
 pub struct PoprfPreparedTweak<CS: CipherSuite>(
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
     <CS::Group as Group>::Scalar,
-)
+);
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>;
 
 /// Contains the fields that are returned by a partially verifiable server batch
 /// evaluate prepare
 #[derive_where(Debug; I, <CS::Group as Group>::Scalar)]
-pub struct PoprfServerBatchEvaluatePrepareResult<CS: CipherSuite, I>
+pub struct PoprfServerBatchEvaluatePrepareResult<CS: CipherSuite, I> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Prepared [`EvaluationElement`].
     pub prepared_evaluation_elements: PoprfServerBatchEvaluatePreparedEvaluationElements<CS, I>,
     /// Prepared tweak.
@@ -575,8 +532,6 @@ pub type PoprfServerBatchEvaluateFinishedMessages<'a, CS, I> = Map<
 #[derive_where(Debug; <&'a I as IntoIterator>::IntoIter, <CS::Group as Group>::Scalar)]
 pub struct PoprfServerBatchEvaluateFinishResult<'a, CS: 'a + CipherSuite, I>
 where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
     &'a I: IntoIterator<Item = &'a PreparedEvaluationElement<CS>>,
 {
     /// The [`EvaluationElement`]s to send to the client
@@ -597,11 +552,7 @@ where
 fn compute_tweaked_key<CS: CipherSuite>(
     pk: <CS::Group as Group>::Elem,
     info: Option<&[u8]>,
-) -> Result<<CS::Group as Group>::Elem>
+) -> Result<<CS::Group as Group>::Elem> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     // None for info is treated the same as empty bytes
     let info = info.unwrap_or_default();
 
@@ -614,7 +565,7 @@ where
     let info_len = i2osp_2(info.len()).map_err(|_| Error::Info)?;
     let framed_info = [STR_INFO.as_slice(), &info_len, info];
 
-    let dst = Dst::new::<CS, _, _>(STR_HASH_TO_SCALAR, Mode::Poprf);
+    let dst = Dst::new::<CS, _>(STR_HASH_TO_SCALAR, Mode::Poprf);
     // This can't fail, the size of the `input` is known.
     let m = CS::Group::hash_to_scalar::<CS::Hash>(&framed_info, &dst.as_dst()).unwrap();
 
@@ -635,11 +586,7 @@ where
 fn compute_tweak<CS: CipherSuite>(
     sk: <CS::Group as Group>::Scalar,
     info: Option<&[u8]>,
-) -> Result<<CS::Group as Group>::Scalar>
+) -> Result<<CS::Group as Group>::Scalar> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     // None for info is treated the same as empty bytes
     let info = info.unwrap_or_default();
 
@@ -651,7 +598,7 @@ where
     let info_len = i2osp_2(info.len()).map_err(|_| Error::Info)?;
     let framed_info = [STR_INFO.as_slice(), &info_len, info];
 
-    let dst = Dst::new::<CS, _, _>(STR_HASH_TO_SCALAR, Mode::Poprf);
+    let dst = Dst::new::<CS, _>(STR_HASH_TO_SCALAR, Mode::Poprf);
     // This can't fail, the size of the `input` is known.
     let m = CS::Group::hash_to_scalar::<CS::Hash>(&framed_info, &dst.as_dst()).unwrap();
 
@@ -690,8 +637,6 @@ fn poprf_unblind<'a, CS: 'a + CipherSuite, IC, IM>(
     info: Option<&[u8]>,
 ) -> Result<PoprfUnblindResult<'a, CS, IC, IM>>
 where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
     &'a IC: 'a + IntoIterator<Item = &'a PoprfClient<CS>>,
     <&'a IC as IntoIterator>::IntoIter: ExactSizeIterator,
     &'a IM: 'a + IntoIterator<Item = &'a EvaluationElement<CS>>,
@@ -719,7 +664,7 @@ where
     )?;
 
     Ok(blinds
-        .zip(messages.into_iter())
+        .zip(messages)
         .map(|(blind, x)| x.0 * &CS::Group::invert_scalar(blind)))
 }
 
@@ -727,7 +672,7 @@ type FinalizeAfterUnblindResult<'a, CS, IE, II> = Map<
     Zip<Zip<IE, II>, Repeat<&'a [u8]>>,
     fn(
         ((<<CS as CipherSuite>::Group as Group>::Elem, &[u8]), &[u8]),
-    ) -> Result<GenericArray<u8, <<CS as CipherSuite>::Hash as OutputSizeUser>::OutputSize>>,
+    ) -> Result<Output<<CS as CipherSuite>::Hash>>,
 >;
 
 /// Can only fail with [`Error::Batch`] and returned values can only fail with
@@ -743,8 +688,7 @@ fn finalize_after_unblind<
     info: Option<&'a [u8]>,
 ) -> Result<FinalizeAfterUnblindResult<'a, CS, IE, II>>
 where
-    <CS::Hash as OutputSizeUser>::OutputSize:
+    <<CS as CipherSuite>::Hash as OutputSizeUser>::OutputSize: ArraySize,
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
 {
     if unblinded_elements.len() != inputs.len() {
         return Err(Error::Batch);
@@ -783,30 +727,23 @@ where
 
 #[cfg(test)]
 mod tests {
-    use core::ops::Add;
     use core::ptr;
 
-    use generic_array::typenum::Sum;
+    use rand::rngs::SysRng;
-    use generic_array::ArrayLength;
-    use rand::rngs::OsRng;
 
     use super::*;
-    use crate::common::STR_HASH_TO_GROUP;
     use crate::Group;
+    use crate::common::STR_HASH_TO_GROUP;
 
     fn prf<CS: CipherSuite>(
         input: &[u8],
         key: <CS::Group as Group>::Scalar,
         info: &[u8],
         mode: Mode,
-    ) -> Output<CS::Hash>
+    ) -> Output<CS::Hash> {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let t = compute_tweak::<CS>(key, Some(info)).unwrap();
 
-        let dst = Dst::new::<CS, _, _>(STR_HASH_TO_GROUP, mode);
+        let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, mode);
         let point = CS::Group::hash_to_curve::<CS::Hash>(&[input], &dst.as_dst()).unwrap();
 
         // evaluatedElement = G.ScalarInverse(t) * blindedElement
@@ -819,14 +756,10 @@ mod tests {
             .unwrap()
     }
 
-    fn verifiable_retrieval<CS: CipherSuite>()
+    fn verifiable_retrieval<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
         let info = b"info";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let server = PoprfServer::<CS>::new(&mut rng).unwrap();
         let client_blind_result = PoprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server_result = server
@@ -846,21 +779,17 @@ mod tests {
         assert_eq!(client_finalize_result, res2);
     }
 
-    fn verifiable_bad_public_key<CS: CipherSuite>()
+    fn verifiable_bad_public_key<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
         let info = b"info";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let server = PoprfServer::<CS>::new(&mut rng).unwrap();
         let client_blind_result = PoprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server_result = server
             .blind_evaluate(&mut rng, &client_blind_result.message, Some(info))
             .unwrap();
         let wrong_pk = {
-            let dst = Dst::new::<CS, _, _>(STR_HASH_TO_GROUP, Mode::Oprf);
+            let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, Mode::Oprf);
             // Choose a group element that is unlikely to be the right public key
             CS::Group::hash_to_curve::<CS::Hash>(&[b"msg"], &dst.as_dst()).unwrap()
         };
@@ -874,14 +803,10 @@ mod tests {
         assert!(client_finalize_result.is_err());
     }
 
-    fn verifiable_server_evaluate<CS: CipherSuite>()
+    fn verifiable_server_evaluate<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
         let info = Some(b"info".as_slice());
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = PoprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server = PoprfServer::<CS>::new(&mut rng).unwrap();
         let server_result = server
@@ -911,15 +836,9 @@ mod tests {
         assert!(client_finalize != server_evaluate);
     }
 
-    fn zeroize_verifiable_client<CS: CipherSuite>()
+    fn zeroize_verifiable_client<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ElemLen>,
-        Sum<<CS::Group as Group>::ScalarLen, <CS::Group as Group>::ElemLen>: ArrayLength<u8>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = PoprfClient::<CS>::blind(input, &mut rng).unwrap();
 
         let mut state = client_blind_result.state;
@@ -931,18 +850,10 @@ mod tests {
         assert!(message.serialize().iter().all(|&x| x == 0));
     }
 
-    fn zeroize_verifiable_server<CS: CipherSuite>()
+    fn zeroize_verifiable_server<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ElemLen>,
-        Sum<<CS::Group as Group>::ScalarLen, <CS::Group as Group>::ElemLen>: ArrayLength<u8>,
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ScalarLen>,
-        Sum<<CS::Group as Group>::ScalarLen, <CS::Group as Group>::ScalarLen>: ArrayLength<u8>,
-    {
         let input = b"input";
         let info = b"info";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let server = PoprfServer::<CS>::new(&mut rng).unwrap();
         let client_blind_result = PoprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server_result = server
@@ -966,6 +877,7 @@ mod tests {
     fn test_functionality() -> Result<()> {
         use p256::NistP256;
         use p384::NistP384;
+        use p521::NistP521;
 
         #[cfg(feature = "ristretto255")]
         {
@@ -993,6 +905,13 @@ mod tests {
         zeroize_verifiable_client::<NistP384>();
         zeroize_verifiable_server::<NistP384>();
 
+        verifiable_retrieval::<NistP521>();
+        verifiable_bad_public_key::<NistP521>();
+        verifiable_server_evaluate::<NistP521>();
+
+        zeroize_verifiable_client::<NistP521>();
+        zeroize_verifiable_server::<NistP521>();
+
         Ok(())
     }
 }

src/serialization.rs

@@ -1,20 +1,12 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Handles the serialization of each of the components used in the VOPRF
 //! protocol
 
-use core::ops::Add;
+use hybrid_array::Array;
-
+use hybrid_array::typenum::{Sum, Unsigned};
-use digest::core_api::BlockSizeUser;
-use digest::OutputSizeUser;
-use generic_array::sequence::Concat;
-use generic_array::typenum::{IsLess, IsLessOrEqual, Sum, Unsigned, U256};
-use generic_array::{ArrayLength, GenericArray};
 
 use crate::{
     BlindedElement, CipherSuite, Error, EvaluationElement, Group, OprfClient, OprfServer,
@@ -29,13 +21,9 @@ use crate::{
 /// Length of [`OprfClient`] in bytes for serialization.
 pub type OprfClientLen<CS> = <<CS as CipherSuite>::Group as Group>::ScalarLen;
 
-impl<CS: CipherSuite> OprfClient<CS>
+impl<CS: CipherSuite> OprfClient<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, OprfClientLen<CS>> {
+    pub fn serialize(&self) -> Array<u8, OprfClientLen<CS>> {
         CS::Group::serialize_scalar(self.blind)
     }
 
@@ -46,6 +34,10 @@ where
     pub fn deserialize(mut input: &[u8]) -> Result<Self> {
         let blind = deserialize_scalar::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Self { blind })
     }
 }
@@ -56,17 +48,9 @@ pub type VoprfClientLen<CS> = Sum<
     <<CS as CipherSuite>::Group as Group>::ElemLen,
 >;
 
-impl<CS: CipherSuite> VoprfClient<CS>
+impl<CS: CipherSuite> VoprfClient<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, VoprfClientLen<CS>>
+    pub fn serialize(&self) -> Array<u8, VoprfClientLen<CS>> {
-    where
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ElemLen>,
-        VoprfClientLen<CS>: ArrayLength<u8>,
-    {
         <CS::Group as Group>::serialize_scalar(self.blind)
             .concat(<CS::Group as Group>::serialize_elem(self.blinded_element))
     }
@@ -79,6 +63,10 @@ where
         let blind = deserialize_scalar::<CS::Group>(&mut input)?;
         let blinded_element = deserialize_elem::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Self {
             blind,
             blinded_element,
@@ -92,17 +80,9 @@ pub type PoprfClientLen<CS> = Sum<
     <<CS as CipherSuite>::Group as Group>::ElemLen,
 >;
 
-impl<CS: CipherSuite> PoprfClient<CS>
+impl<CS: CipherSuite> PoprfClient<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, PoprfClientLen<CS>>
+    pub fn serialize(&self) -> Array<u8, PoprfClientLen<CS>> {
-    where
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ElemLen>,
-        PoprfClientLen<CS>: ArrayLength<u8>,
-    {
         <CS::Group as Group>::serialize_scalar(self.blind)
             .concat(<CS::Group as Group>::serialize_elem(self.blinded_element))
     }
@@ -115,6 +95,10 @@ where
         let blind = deserialize_scalar::<CS::Group>(&mut input)?;
         let blinded_element = deserialize_elem::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Self {
             blind,
             blinded_element,
@@ -125,13 +109,9 @@ where
 /// Length of [`OprfServer`] in bytes for serialization.
 pub type OprfServerLen<CS> = <<CS as CipherSuite>::Group as Group>::ScalarLen;
 
-impl<CS: CipherSuite> OprfServer<CS>
+impl<CS: CipherSuite> OprfServer<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, OprfServerLen<CS>> {
+    pub fn serialize(&self) -> Array<u8, OprfServerLen<CS>> {
         CS::Group::serialize_scalar(self.sk)
     }
 
@@ -142,6 +122,10 @@ where
     pub fn deserialize(mut input: &[u8]) -> Result<Self> {
         let sk = deserialize_scalar::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Self { sk })
     }
 }
@@ -152,17 +136,9 @@ pub type VoprfServerLen<CS> = Sum<
     <<CS as CipherSuite>::Group as Group>::ElemLen,
 >;
 
-impl<CS: CipherSuite> VoprfServer<CS>
+impl<CS: CipherSuite> VoprfServer<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, VoprfServerLen<CS>>
+    pub fn serialize(&self) -> Array<u8, VoprfServerLen<CS>> {
-    where
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ElemLen>,
-        VoprfServerLen<CS>: ArrayLength<u8>,
-    {
         CS::Group::serialize_scalar(self.sk).concat(CS::Group::serialize_elem(self.pk))
     }
 
@@ -174,6 +150,10 @@ where
         let sk = deserialize_scalar::<CS::Group>(&mut input)?;
         let pk = deserialize_elem::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Self { sk, pk })
     }
 }
@@ -184,17 +164,9 @@ pub type PoprfServerLen<CS> = Sum<
     <<CS as CipherSuite>::Group as Group>::ElemLen,
 >;
 
-impl<CS: CipherSuite> PoprfServer<CS>
+impl<CS: CipherSuite> PoprfServer<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, PoprfServerLen<CS>>
+    pub fn serialize(&self) -> Array<u8, PoprfServerLen<CS>> {
-    where
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ElemLen>,
-        PoprfServerLen<CS>: ArrayLength<u8>,
-    {
         CS::Group::serialize_scalar(self.sk).concat(CS::Group::serialize_elem(self.pk))
     }
 
@@ -206,6 +178,10 @@ where
         let sk = deserialize_scalar::<CS::Group>(&mut input)?;
         let pk = deserialize_elem::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Self { sk, pk })
     }
 }
@@ -216,17 +192,9 @@ pub type ProofLen<CS> = Sum<
     <<CS as CipherSuite>::Group as Group>::ScalarLen,
 >;
 
-impl<CS: CipherSuite> Proof<CS>
+impl<CS: CipherSuite> Proof<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, ProofLen<CS>>
+    pub fn serialize(&self) -> Array<u8, ProofLen<CS>> {
-    where
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ScalarLen>,
-        ProofLen<CS>: ArrayLength<u8>,
-    {
         CS::Group::serialize_scalar(self.c_scalar)
             .concat(CS::Group::serialize_scalar(self.s_scalar))
     }
@@ -239,6 +207,10 @@ where
         let c_scalar = deserialize_scalar::<CS::Group>(&mut input)?;
         let s_scalar = deserialize_scalar::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Proof { c_scalar, s_scalar })
     }
 }
@@ -246,13 +218,9 @@ where
 /// Length of [`BlindedElement`] in bytes for serialization.
 pub type BlindedElementLen<CS> = <<CS as CipherSuite>::Group as Group>::ElemLen;
 
-impl<CS: CipherSuite> BlindedElement<CS>
+impl<CS: CipherSuite> BlindedElement<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, BlindedElementLen<CS>> {
+    pub fn serialize(&self) -> Array<u8, BlindedElementLen<CS>> {
         CS::Group::serialize_elem(self.0)
     }
 
@@ -263,6 +231,10 @@ where
     pub fn deserialize(mut input: &[u8]) -> Result<Self> {
         let value = deserialize_elem::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Self(value))
     }
 }
@@ -270,13 +242,9 @@ where
 /// Length of [`EvaluationElement`] in bytes for serialization.
 pub type EvaluationElementLen<CS> = <<CS as CipherSuite>::Group as Group>::ElemLen;
 
-impl<CS: CipherSuite> EvaluationElement<CS>
+impl<CS: CipherSuite> EvaluationElement<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Serialization into bytes
-    pub fn serialize(&self) -> GenericArray<u8, EvaluationElementLen<CS>> {
+    pub fn serialize(&self) -> Array<u8, EvaluationElementLen<CS>> {
         CS::Group::serialize_elem(self.0)
     }
 
@@ -287,6 +255,10 @@ where
     pub fn deserialize(mut input: &[u8]) -> Result<Self> {
         let value = deserialize_elem::<CS::Group>(&mut input)?;
 
+        if !input.is_empty() {
+            return Err(Error::Deserialization);
+        }
+
         Ok(Self(value))
     }
 }
@@ -306,11 +278,11 @@ fn deserialize_scalar<G: Group>(input: &mut &[u8]) -> Result<G::Scalar> {
 }
 
 trait SliceExt {
-    fn take_ext(self: &mut &Self, take: usize) -> Option<&Self>;
+    fn take_ext<'a>(self: &mut &'a Self, take: usize) -> Option<&'a Self>;
 }
 
 impl<T> SliceExt for [T] {
-    fn take_ext(self: &mut &Self, take: usize) -> Option<&Self> {
+    fn take_ext<'a>(self: &mut &'a Self, take: usize) -> Option<&'a Self> {
         if take > self.len() {
             return None;
         }
@@ -325,7 +297,7 @@ impl<T> SliceExt for [T] {
 pub(crate) mod serde {
     use core::marker::PhantomData;
 
-    use generic_array::GenericArray;
+    use hybrid_array::Array;
     use serde::de::{Deserializer, Error};
     use serde::ser::Serializer;
     use serde::{Deserialize, Serialize};
@@ -339,7 +311,7 @@ pub(crate) mod serde {
         where
             D: Deserializer<'de>,
         {
-            GenericArray::<_, G::ElemLen>::deserialize(deserializer)
+            Array::<_, G::ElemLen>::deserialize(deserializer)
                 .and_then(|bytes| G::deserialize_elem(&bytes).map_err(D::Error::custom))
         }
 
@@ -358,7 +330,7 @@ pub(crate) mod serde {
         where
             D: Deserializer<'de>,
         {
-            GenericArray::<_, G::ScalarLen>::deserialize(deserializer)
+            Array::<_, G::ScalarLen>::deserialize(deserializer)
                 .and_then(|bytes| G::deserialize_scalar(&bytes).map_err(D::Error::custom))
         }
 
@@ -381,6 +353,7 @@ mod test {
         VoprfClient, VoprfServer,
     };
 
+    // Fuzz: no panics on arbitrary input
     macro_rules! test_deserialize {
         ($item:ident, $bytes:ident) => {
             #[cfg(feature = "ristretto255")]
@@ -388,11 +361,43 @@ mod test {
                 let _ = $item::<crate::Ristretto255>::deserialize(&$bytes[..]);
             }
 
-            let _ = $item::<p256::NistP256>::deserialize(&$bytes[..]);
+            let _ = $item::<::p256::NistP256>::deserialize(&$bytes[..]);
-            let _ = $item::<p384::NistP384>::deserialize(&$bytes[..]);
+            let _ = $item::<::p384::NistP384>::deserialize(&$bytes[..]);
+            let _ = $item::<::p521::NistP521>::deserialize(&$bytes[..]);
         };
     }
 
+    // Roundtrip: serialize to deserialize == original
+    macro_rules! test_roundtrip {
+        ($item:ident, $cs:ty, $constructor:expr) => {{
+            let original = $constructor;
+            let bytes = original.serialize();
+            let recovered = $item::<$cs>::deserialize(&bytes).expect("roundtrip deserialize");
+            assert_eq!(original.serialize(), recovered.serialize());
+        }};
+    }
+
+    // Trailing bytes: valid serialization + extra byte must fail
+    macro_rules! test_trailing {
+        ($item:ident, $cs:ty, $constructor:expr) => {{
+            let original = $constructor;
+            let bytes = original.serialize();
+            let mut extended = bytes.to_vec();
+            extended.push(0x00);
+            assert!($item::<$cs>::deserialize(&extended).is_err());
+        }};
+    }
+
+    // Truncated: valid serialization minus one byte must fail
+    macro_rules! test_truncated {
+        ($item:ident, $cs:ty, $constructor:expr) => {{
+            let original = $constructor;
+            let bytes = original.serialize();
+            let truncated = &bytes[..bytes.len() - 1];
+            assert!($item::<$cs>::deserialize(truncated).is_err());
+        }};
+    }
+
     proptest! {
         #[test]
         fn test_nocrash_oprf_client(bytes in vec(any::<u8>(), 0..200)) {
@@ -440,4 +445,103 @@ mod test {
             test_deserialize!(Proof, bytes);
         }
     }
+
+    macro_rules! structured_tests {
+        ($cs:ty, $mod:ident) => {
+            mod $mod {
+                use super::*;
+
+                use rand::rngs::SysRng;
+
+                #[test]
+                fn roundtrip_oprf_client() {
+                    let client = OprfClient::<$cs>::blind(b"input", &mut SysRng)
+                        .expect("blind")
+                        .state;
+                    test_roundtrip!(OprfClient, $cs, client);
+                }
+
+                #[test]
+                fn roundtrip_oprf_server() {
+                    let server = OprfServer::<$cs>::new(&mut SysRng).expect("new");
+                    test_roundtrip!(OprfServer, $cs, server);
+                }
+
+                #[test]
+                fn roundtrip_voprf_client() {
+                    let client = VoprfClient::<$cs>::blind(b"input", &mut SysRng)
+                        .expect("blind")
+                        .state;
+                    test_roundtrip!(VoprfClient, $cs, client);
+                }
+
+                #[test]
+                fn roundtrip_voprf_server() {
+                    let server = VoprfServer::<$cs>::new(&mut SysRng).expect("new");
+                    test_roundtrip!(VoprfServer, $cs, server);
+                }
+
+                #[test]
+                fn roundtrip_poprf_client() {
+                    let client = PoprfClient::<$cs>::blind(b"input", &mut SysRng)
+                        .expect("blind")
+                        .state;
+                    test_roundtrip!(PoprfClient, $cs, client);
+                }
+
+                #[test]
+                fn roundtrip_poprf_server() {
+                    let server = PoprfServer::<$cs>::new(&mut SysRng).expect("new");
+                    test_roundtrip!(PoprfServer, $cs, server);
+                }
+
+                #[test]
+                fn trailing_oprf_client() {
+                    let client = OprfClient::<$cs>::blind(b"input", &mut SysRng)
+                        .expect("blind")
+                        .state;
+                    test_trailing!(OprfClient, $cs, client);
+                }
+
+                #[test]
+                fn trailing_oprf_server() {
+                    let server = OprfServer::<$cs>::new(&mut SysRng).expect("new");
+                    test_trailing!(OprfServer, $cs, server);
+                }
+
+                #[test]
+                fn truncated_oprf_client() {
+                    let client = OprfClient::<$cs>::blind(b"input", &mut SysRng)
+                        .expect("blind")
+                        .state;
+                    test_truncated!(OprfClient, $cs, client);
+                }
+
+                #[test]
+                fn truncated_oprf_server() {
+                    let server = OprfServer::<$cs>::new(&mut SysRng).expect("new");
+                    test_truncated!(OprfServer, $cs, server);
+                }
+
+                #[test]
+                fn empty_input_fails() {
+                    assert!(OprfClient::<$cs>::deserialize(&[]).is_err());
+                    assert!(OprfServer::<$cs>::deserialize(&[]).is_err());
+                    assert!(VoprfClient::<$cs>::deserialize(&[]).is_err());
+                    assert!(VoprfServer::<$cs>::deserialize(&[]).is_err());
+                    assert!(PoprfClient::<$cs>::deserialize(&[]).is_err());
+                    assert!(PoprfServer::<$cs>::deserialize(&[]).is_err());
+                    assert!(BlindedElement::<$cs>::deserialize(&[]).is_err());
+                    assert!(EvaluationElement::<$cs>::deserialize(&[]).is_err());
+                    assert!(Proof::<$cs>::deserialize(&[]).is_err());
+                }
+            }
+        };
+    }
+
+    #[cfg(feature = "ristretto255")]
+    structured_tests!(crate::Ristretto255, ristretto255);
+    structured_tests!(::p256::NistP256, p256);
+    structured_tests!(::p384::NistP384, p384);
+    structured_tests!(::p521::NistP521, p521);
 }

src/tests/mock_rng.rs

@@ -1,14 +1,12 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 use alloc::vec::Vec;
 use core::cmp::min;
 
-use rand_core::{CryptoRng, Error, RngCore};
+use core::convert::Infallible;
+use rand_core::{TryCryptoRng, TryRng};
 
 /// A simple implementation of `RngCore` for testing purposes.
 ///
@@ -37,29 +35,35 @@ fn rotate_left<T>(data: &mut [T], steps: usize) {
     data.reverse();
 }
 
-impl RngCore for CycleRng {
+impl TryRng for CycleRng {
-    fn next_u32(&mut self) -> u32 {
+    type Error = Infallible;
-        unimplemented!()
+
+    fn try_next_u32(&mut self) -> Result<u32, Self::Error> {
+        let mut buf = [0u8; 4];
+
+        self.try_fill_bytes(&mut buf)?;
+
+        Ok(u32::from_le_bytes(buf))
     }
 
-    #[inline]
+    fn try_next_u64(&mut self) -> Result<u64, Self::Error> {
-    fn next_u64(&mut self) -> u64 {
+        let mut buf = [0u8; 8];
-        unimplemented!()
+
+        self.try_fill_bytes(&mut buf)?;
+
+        Ok(u64::from_le_bytes(buf))
     }
 
-    #[inline]
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Self::Error> {
-    fn fill_bytes(&mut self, dest: &mut [u8]) {
         let len = min(self.v.len(), dest.len());
-        dest[..len].copy_from_slice(&self.v[..len]);
-        rotate_left(&mut self.v, len);
-    }
 
-    #[inline]
+        dest[..len].copy_from_slice(&self.v[..len]);
-    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+
-        self.fill_bytes(dest);
+        rotate_left(&mut self.v, len);
+
         Ok(())
     }
 }
 
 // This is meant for testing only
-impl CryptoRng for CycleRng {}
+impl TryCryptoRng for CycleRng {}

src/tests/mod.rs

@@ -1,9 +1,6 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 mod cfrg_vectors;
 mod mock_rng;

src/tests/parser.rs

@@ -1,9 +1,6 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 use alloc::string::{String, ToString};
 use alloc::vec::Vec;
@@ -14,55 +11,50 @@ pub(crate) fn rfc_to_json(input: &str) -> String {
 }
 
 fn parse_ciphersuites(input: &str) -> String {
-    let re = regex::Regex::new(r"\n## (?P<ciphersuite>.+?)\n").unwrap();
+    let re = regex::Regex::new(r"\nA\.\d\. {2}(?P<ciphersuite>.+?)\n\n").unwrap();
     let mut ciphersuites = vec![];
 
     let chunks: Vec<&str> = re.split(input).collect();
-    let mut count = 1;
+    for (count, caps) in (1..).zip(re.captures_iter(input)) {
-    for caps in re.captures_iter(input) {
         let ciphersuite = format!(
             "\"{}\": {{ {} }}",
             &caps["ciphersuite"],
             parse_modes(chunks[count])
         );
+
         ciphersuites.push(ciphersuite);
-        count += 1;
     }
 
     ciphersuites.join(",\n")
 }
 
 fn parse_modes(input: &str) -> String {
-    let re = regex::Regex::new(r"### (?P<mode>.*+) Mode").unwrap();
+    let re = regex::Regex::new(r"A\.\d.\d\. {2}(?P<mode>.*?) Mode").unwrap();
     let mut modes = vec![];
 
     let chunks: Vec<&str> = re.split(input).collect();
-    let mut count = 1;
+    for (count, caps) in (1..).zip(re.captures_iter(input)) {
-    for caps in re.captures_iter(input) {
         let mode = format!(
             "\"{}\": [\n {} \n]",
             &caps["mode"],
             parse_vectors(chunks[count])
         );
         modes.push(mode);
-        count += 1;
     }
 
     modes.join(",\n")
 }
 
 fn parse_vectors(input: &str) -> String {
-    let re = regex::Regex::new(r"Test Vector.*+\n").unwrap();
+    let re = regex::Regex::new(r"A\.\d.\d\.\d\. {2}Test Vector.*+\n").unwrap();
     let mut vectors = vec![];
 
     let chunks: Vec<&str> = re.split(input).collect();
     let init_params = parse_params(chunks[0]);
 
-    let mut count = 1;
+    for (count, _) in (1..).zip(re.captures_iter(input)) {
-    for _ in re.captures_iter(input) {
         let params = format!("{{\n{},\n{}\n}}", init_params, parse_params(chunks[count]));
         vectors.push(params);
-        count += 1;
     }
 
     vectors.join(",\n")

src/tests/test_cfrg_vectors.rs

@@ -1,19 +1,11 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 use alloc::string::String;
 use alloc::vec;
 use alloc::vec::Vec;
-use core::ops::Add;
 
-use digest::core_api::BlockSizeUser;
-use digest::OutputSizeUser;
-use generic_array::typenum::{IsLess, IsLessOrEqual, Sum, U256};
-use generic_array::ArrayLength;
 use serde_json::Value;
 
 use crate::tests::mock_rng::CycleRng;
@@ -88,6 +80,7 @@ macro_rules! json_to_test_vectors {
 fn test_vectors() -> Result<()> {
     use p256::NistP256;
     use p384::NistP384;
+    use p521::NistP521;
 
     let rfc: Value = serde_json::from_str(rfc_to_json(super::cfrg_vectors::VECTORS).as_str())
         .expect("Could not parse json");
@@ -187,14 +180,37 @@ fn test_vectors() -> Result<()> {
     test_poprf_finalize::<NistP384>(&p384_poprf_tvs)?;
     test_poprf_evaluate::<NistP384>(&p384_poprf_tvs)?;
 
+    let p521_oprf_tvs =
+        json_to_test_vectors!(rfc, String::from("P521-SHA512"), String::from("OPRF"));
+    assert_ne!(p521_oprf_tvs.len(), 0);
+    test_oprf_seed_to_key::<NistP521>(&p521_oprf_tvs)?;
+    test_oprf_blind::<NistP521>(&p521_oprf_tvs)?;
+    test_oprf_blind_evaluate::<NistP521>(&p521_oprf_tvs)?;
+    test_oprf_finalize::<NistP521>(&p521_oprf_tvs)?;
+    test_oprf_evaluate::<NistP521>(&p521_oprf_tvs)?;
+
+    let p521_voprf_tvs =
+        json_to_test_vectors!(rfc, String::from("P521-SHA512"), String::from("VOPRF"));
+    assert_ne!(p521_voprf_tvs.len(), 0);
+    test_voprf_seed_to_key::<NistP521>(&p521_voprf_tvs)?;
+    test_voprf_blind::<NistP521>(&p521_voprf_tvs)?;
+    test_voprf_blind_evaluate::<NistP521>(&p521_voprf_tvs)?;
+    test_voprf_finalize::<NistP521>(&p521_voprf_tvs)?;
+    test_voprf_evaluate::<NistP521>(&p521_voprf_tvs)?;
+
+    let p521_poprf_tvs =
+        json_to_test_vectors!(rfc, String::from("P521-SHA512"), String::from("POPRF"));
+    assert_ne!(p521_poprf_tvs.len(), 0);
+    test_poprf_seed_to_key::<NistP521>(&p521_poprf_tvs)?;
+    test_poprf_blind::<NistP521>(&p521_poprf_tvs)?;
+    test_poprf_blind_evaluate::<NistP521>(&p521_poprf_tvs)?;
+    test_poprf_finalize::<NistP521>(&p521_poprf_tvs)?;
+    test_poprf_evaluate::<NistP521>(&p521_poprf_tvs)?;
+
     Ok(())
 }
 
-fn test_oprf_seed_to_key<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_oprf_seed_to_key<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         let server = OprfServer::<CS>::new_from_seed(&parameters.seed, &parameters.key_info)?;
 
@@ -206,11 +222,7 @@ where
     Ok(())
 }
 
-fn test_voprf_seed_to_key<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_voprf_seed_to_key<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         let server = VoprfServer::<CS>::new_from_seed(&parameters.seed, &parameters.key_info)?;
 
@@ -226,11 +238,7 @@ where
     Ok(())
 }
 
-fn test_poprf_seed_to_key<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_poprf_seed_to_key<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         let server = PoprfServer::<CS>::new_from_seed(&parameters.seed, &parameters.key_info)?;
 
@@ -247,11 +255,7 @@ where
 }
 
 // Tests input -> blind, blinded_element
-fn test_oprf_blind<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_oprf_blind<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         for i in 0..parameters.input.len() {
             let blind = CS::Group::deserialize_scalar(&parameters.blind[i])?;
@@ -272,11 +276,7 @@ where
 }
 
 // Tests input -> blind, blinded_element
-fn test_voprf_blind<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_voprf_blind<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         for i in 0..parameters.input.len() {
             let blind = CS::Group::deserialize_scalar(&parameters.blind[i])?;
@@ -297,11 +297,7 @@ where
 }
 
 // Tests input -> blind, blinded_element
-fn test_poprf_blind<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_poprf_blind<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         for i in 0..parameters.input.len() {
             let blind = CS::Group::deserialize_scalar(&parameters.blind[i])?;
@@ -322,11 +318,7 @@ where
 }
 
 // Tests sksm, blinded_element -> evaluation_element
-fn test_oprf_blind_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_oprf_blind_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         for i in 0..parameters.input.len() {
             let server = OprfServer::<CS>::new_with_key(&parameters.sksm)?;
@@ -343,13 +335,7 @@ where
     Ok(())
 }
 
-fn test_voprf_blind_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_voprf_blind_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ScalarLen>,
-    Sum<<CS::Group as Group>::ScalarLen, <CS::Group as Group>::ScalarLen>: ArrayLength<u8>,
-{
     for parameters in tvs {
         let mut rng = CycleRng::new(parameters.proof_random_scalar.clone());
         let server = VoprfServer::<CS>::new_with_key(&parameters.sksm)?;
@@ -370,18 +356,12 @@ where
             assert_eq!(&parameter, &message.serialize().as_slice());
         }
 
-        assert_eq!(&parameters.proof, &proof.serialize().as_slice());
+        assert_eq!(&parameters.proof, &proof.serialize().to_vec());
     }
     Ok(())
 }
 
-fn test_poprf_blind_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_poprf_blind_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ScalarLen>,
-    Sum<<CS::Group as Group>::ScalarLen, <CS::Group as Group>::ScalarLen>: ArrayLength<u8>,
-{
     for parameters in tvs {
         let mut rng = CycleRng::new(parameters.proof_random_scalar.clone());
         let server = PoprfServer::<CS>::new_with_key(&parameters.sksm)?;
@@ -402,8 +382,7 @@ where
                 blinded_elements.iter(),
                 &prepared_evaluation_elements,
                 &prepared_tweak,
-            )
+            )?;
-            .unwrap();
 
         let messages: Vec<_> = messages.collect();
 
@@ -411,17 +390,13 @@ where
             assert_eq!(&parameter, &message.serialize().as_slice());
         }
 
-        assert_eq!(&parameters.proof, &proof.serialize().as_slice());
+        assert_eq!(&parameters.proof, &proof.serialize().to_vec());
     }
     Ok(())
 }
 
 // Tests input, blind, evaluation_element -> output
-fn test_oprf_finalize<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_oprf_finalize<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         for i in 0..parameters.input.len() {
             let client =
@@ -438,11 +413,7 @@ where
     Ok(())
 }
 
-fn test_voprf_finalize<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_voprf_finalize<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         let mut clients = vec![];
         for i in 0..parameters.input.len() {
@@ -477,11 +448,7 @@ where
     Ok(())
 }
 
-fn test_poprf_finalize<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_poprf_finalize<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         let mut clients = vec![];
         for i in 0..parameters.input.len() {
@@ -515,11 +482,7 @@ where
 }
 
 // Tests input, sksm -> output
-fn test_oprf_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_oprf_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         for i in 0..parameters.input.len() {
             let server = OprfServer::<CS>::new_with_key(&parameters.sksm)?;
@@ -532,11 +495,7 @@ where
     Ok(())
 }
 
-fn test_voprf_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_voprf_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         for i in 0..parameters.input.len() {
             let server = VoprfServer::<CS>::new_with_key(&parameters.sksm)?;
@@ -549,11 +508,7 @@ where
     Ok(())
 }
 
-fn test_poprf_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()>
+fn test_poprf_evaluate<CS: CipherSuite>(tvs: &[VOPRFTestVectorParameters]) -> Result<()> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     for parameters in tvs {
         for i in 0..parameters.input.len() {
             let server = PoprfServer::<CS>::new_with_key(&parameters.sksm)?;

src/voprf.rs

@@ -1,9 +1,6 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
+// SPDX-License-Identifier: MIT OR Apache-2.0
-//
+// Copyright (c) VexaHub and contributors.
-// This source code is licensed under both the MIT license found in the
+// Copyright (c) Meta Platforms, Inc. and affiliates.
-// LICENSE-MIT file in the root directory of this source tree and the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree.
 
 //! Contains the main VOPRF API
 
@@ -12,16 +9,15 @@ use alloc::vec::Vec;
 use core::iter::{self, Map, Repeat, Zip};
 
 use derive_where::derive_where;
-use digest::core_api::BlockSizeUser;
+use digest::{Digest, Output};
-use digest::{Digest, Output, OutputSizeUser};
+use hybrid_array::Array;
-use generic_array::typenum::{IsLess, IsLessOrEqual, Unsigned, U256};
+use hybrid_array::typenum::Unsigned;
-use generic_array::GenericArray;
+use rand_core::{TryCryptoRng, TryRng};
-use rand_core::{CryptoRng, RngCore};
 
 use crate::common::{
+    BlindedElement, EvaluationElement, Mode, PreparedEvaluationElement, Proof, STR_FINALIZE,
     derive_keypair, deterministic_blind_unchecked, generate_proof, hash_to_group, i2osp_2,
-    server_evaluate_hash_input, verify_proof, BlindedElement, EvaluationElement, Mode,
+    server_evaluate_hash_input, verify_proof,
-    PreparedEvaluationElement, Proof, STR_FINALIZE,
 };
 #[cfg(feature = "serde")]
 use crate::serialization::serde::{Element, Scalar};
@@ -41,11 +37,7 @@ use crate::{CipherSuite, Error, Group, Result};
     derive(serde::Deserialize, serde::Serialize),
     serde(bound = "")
 )]
-pub struct VoprfClient<CS: CipherSuite>
+pub struct VoprfClient<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
     pub(crate) blind: <CS::Group as Group>::Scalar,
     #[cfg_attr(feature = "serde", serde(with = "Element::<CS::Group>"))]
@@ -61,11 +53,7 @@ where
     derive(serde::Deserialize, serde::Serialize),
     serde(bound = "")
 )]
-pub struct VoprfServer<CS: CipherSuite>
+pub struct VoprfServer<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     #[cfg_attr(feature = "serde", serde(with = "Scalar::<CS::Group>"))]
     pub(crate) sk: <CS::Group as Group>::Scalar,
     #[cfg_attr(feature = "serde", serde(with = "Element::<CS::Group>"))]
@@ -77,21 +65,17 @@ where
 // =================== //
 /////////////////////////
 
-impl<CS: CipherSuite> VoprfClient<CS>
+impl<CS: CipherSuite> VoprfClient<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Computes the first step for the multiplicative blinding version of
     /// DH-OPRF.
     ///
     /// # Errors
     /// [`Error::Input`] if the `input` is empty or longer then [`u16::MAX`].
-    pub fn blind<R: RngCore + CryptoRng>(
+    pub fn blind<R: TryRng + TryCryptoRng>(
         input: &[u8],
         blinding_factor_rng: &mut R,
     ) -> Result<VoprfClientBlindResult<CS>> {
-        let blind = CS::Group::random_scalar(blinding_factor_rng);
+        let blind = CS::Group::random_scalar(blinding_factor_rng)?;
         Self::deterministic_blind_unchecked_inner(input, blind)
     }
 
@@ -160,7 +144,7 @@ where
     ///
     /// The resulting messages can each fail individually with [`Error::Input`]
     /// if the `input` is empty or longer then [`u16::MAX`].
-    pub fn batch_finalize<'a, I: 'a, II, IC, IM>(
+    pub fn batch_finalize<'a, I, II, IC, IM>(
         inputs: &'a II,
         clients: &'a IC,
         messages: &'a IM,
@@ -169,7 +153,7 @@ where
     ) -> Result<VoprfClientBatchFinalizeResult<'a, CS, I, II, IC, IM>>
     where
         CS: 'a,
-        I: AsRef<[u8]>,
+        I: 'a + AsRef<[u8]>,
         &'a II: 'a + IntoIterator<Item = I>,
         <&'a II as IntoIterator>::IntoIter: ExactSizeIterator,
         &'a IC: 'a + IntoIterator<Item = &'a VoprfClient<CS>>,
@@ -196,25 +180,21 @@ where
         }
     }
 
-    // Only used for test functions
+    /// Only used for test functions
     #[cfg(test)]
     pub fn get_blind(&self) -> <CS::Group as Group>::Scalar {
         self.blind
     }
 }
 
-impl<CS: CipherSuite> VoprfServer<CS>
+impl<CS: CipherSuite> VoprfServer<CS> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// Produces a new instance of a [VoprfServer] using a supplied RNG
     ///
     /// # Errors
     /// [`Error::Protocol`] if the protocol fails and can't be completed.
-    pub fn new<R: RngCore + CryptoRng>(rng: &mut R) -> Result<Self> {
+    pub fn new<R: TryRng + TryCryptoRng>(rng: &mut R) -> Result<Self> {
-        let mut seed = GenericArray::<_, <CS::Group as Group>::ScalarLen>::default();
+        let mut seed = Array::<_, <CS::Group as Group>::ScalarLen>::default();
-        rng.fill_bytes(&mut seed);
+        rng.try_fill_bytes(&mut seed).map_err(|_| Error::Protocol)?;
         // This can't fail as the hash output is type constrained.
         Self::new_from_seed(&seed, &[])
     }
@@ -245,7 +225,7 @@ where
         Ok(Self { sk, pk })
     }
 
-    // Only used for tests
+    /// Only used for tests
     #[cfg(test)]
     pub fn get_private_key(&self) -> <CS::Group as Group>::Scalar {
         self.sk
@@ -254,7 +234,7 @@ where
     /// Computes the second step for the multiplicative blinding version of
     /// DH-OPRF. This message is sent from the server (who holds the OPRF key)
     /// to the client.
-    pub fn blind_evaluate<R: RngCore + CryptoRng>(
+    pub fn blind_evaluate<R: TryRng + TryCryptoRng>(
         &self,
         rng: &mut R,
         blinded_element: &BlindedElement<CS>,
@@ -287,7 +267,7 @@ where
     /// [`Error::Batch`] if the number of `blinded_elements` and
     /// `evaluation_elements` don't match or is longer then [`u16::MAX`]
     #[cfg(feature = "alloc")]
-    pub fn batch_blind_evaluate<'a, R: RngCore + CryptoRng, I>(
+    pub fn batch_blind_evaluate<'a, R: TryRng + TryCryptoRng, I>(
         &self,
         rng: &mut R,
         blinded_elements: &'a I,
@@ -338,7 +318,7 @@ where
     pub fn batch_blind_evaluate_finish<
         'a,
         'b,
-        R: RngCore + CryptoRng,
+        R: TryRng + TryCryptoRng,
         IB: Iterator<Item = &'a BlindedElement<CS>> + ExactSizeIterator,
         IE,
     >(
@@ -359,14 +339,14 @@ where
             g,
             self.pk,
             blinded_elements.map(|element| element.0),
-            evaluation_elements.into_iter().map(|element| element.0 .0),
+            evaluation_elements.into_iter().map(|element| element.0.0),
             Mode::Voprf,
         )?;
 
         let messages = evaluation_elements.into_iter().map(<fn(
             &PreparedEvaluationElement<CS>,
         ) -> EvaluationElement<CS>>::from(
-            |element| EvaluationElement(element.0 .0),
+            |element| EvaluationElement(element.0.0),
         ));
 
         Ok(VoprfServerBatchEvaluateFinishResult { messages, proof })
@@ -401,11 +381,7 @@ where
 
 /// Contains the fields that are returned by a verifiable client blind
 #[derive_where(Debug; <CS::Group as Group>::Scalar, <CS::Group as Group>::Elem)]
-pub struct VoprfClientBlindResult<CS: CipherSuite>
+pub struct VoprfClientBlindResult<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// The state to be persisted on the client
     pub state: VoprfClient<CS>,
     /// The message to send to the server
@@ -422,11 +398,7 @@ pub type VoprfClientBatchFinalizeResult<'a, C, I, II, IC, IM> = FinalizeAfterUnb
 
 /// Contains the fields that are returned by a verifiable server evaluate
 #[derive_where(Debug; <CS::Group as Group>::Scalar, <CS::Group as Group>::Elem)]
-pub struct VoprfServerEvaluateResult<CS: CipherSuite>
+pub struct VoprfServerEvaluateResult<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// The message to send to the client
     pub message: EvaluationElement<CS>,
     /// The proof for the client to verify
@@ -436,11 +408,7 @@ where
 /// Contains the fields that are returned by a verifiable server batch evaluate
 #[derive_where(Debug; <CS::Group as Group>::Scalar, <CS::Group as Group>::Elem)]
 #[cfg(feature = "alloc")]
-pub struct VoprfServerBatchEvaluateResult<CS: CipherSuite>
+pub struct VoprfServerBatchEvaluateResult<CS: CipherSuite> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     /// The messages to send to the client
     pub messages: Vec<EvaluationElement<CS>>,
     /// The proof for the client to verify
@@ -471,8 +439,6 @@ pub type VoprfServerBatchEvaluateFinishedMessages<'a, CS, I> = Map<
 #[derive_where(Debug; <&'a I as IntoIterator>::IntoIter, <CS::Group as Group>::Scalar)]
 pub struct VoprfServerBatchEvaluateFinishResult<'a, CS: 'a + CipherSuite, I>
 where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
     &'a I: IntoIterator<Item = &'a PreparedEvaluationElement<CS>>,
 {
     /// The [`EvaluationElement`]s to send to the client
@@ -510,8 +476,6 @@ fn verifiable_unblind<'a, CS: 'a + CipherSuite, IC, IM>(
     proof: &Proof<CS>,
 ) -> Result<VoprfUnblindResult<'a, CS, IC, IM>>
 where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
     &'a IC: 'a + IntoIterator<Item = &'a VoprfClient<CS>>,
     <&'a IC as IntoIterator>::IntoIter: ExactSizeIterator,
     &'a IM: 'a + IntoIterator<Item = &'a EvaluationElement<CS>>,
@@ -536,7 +500,7 @@ where
     )?;
 
     Ok(blinds
-        .zip(messages.into_iter())
+        .zip(messages)
         .map(|(blind, x)| x.0 * &CS::Group::invert_scalar(blind)))
 }
 
@@ -553,11 +517,7 @@ fn finalize_after_unblind<
     IE: 'a + Iterator<Item = (I, <CS::Group as Group>::Elem)>,
 >(
     inputs_and_unblinded_elements: IE,
-) -> FinalizeAfterUnblindResult<'a, CS, I, IE>
+) -> FinalizeAfterUnblindResult<'a, CS, I, IE> {
-where
-    <CS::Hash as OutputSizeUser>::OutputSize:
-        IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-{
     inputs_and_unblinded_elements.map(|(input, unblinded_element)| {
         let elem_len = <CS::Group as Group>::ElemLen::U16.to_be_bytes();
 
@@ -582,29 +542,22 @@ where
 
 #[cfg(test)]
 mod tests {
-    use core::ops::Add;
     use core::ptr;
 
     use ::alloc::vec;
     use ::alloc::vec::Vec;
-    use generic_array::typenum::Sum;
+    use rand::rngs::SysRng;
-    use generic_array::ArrayLength;
-    use rand::rngs::OsRng;
 
     use super::*;
-    use crate::common::{Dst, STR_HASH_TO_GROUP};
     use crate::Group;
+    use crate::common::{Dst, STR_HASH_TO_GROUP};
 
     fn prf<CS: CipherSuite>(
         input: &[u8],
         key: <CS::Group as Group>::Scalar,
         mode: Mode,
-    ) -> Output<CS::Hash>
+    ) -> Output<CS::Hash> {
-    where
+        let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, mode);
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
-        let dst = Dst::new::<CS, _, _>(STR_HASH_TO_GROUP, mode);
         let point = CS::Group::hash_to_curve::<CS::Hash>(&[input], &dst.as_dst()).unwrap();
 
         let res = point * &key;
@@ -615,13 +568,9 @@ mod tests {
             .unwrap()
     }
 
-    fn verifiable_retrieval<CS: CipherSuite>()
+    fn verifiable_retrieval<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = VoprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server = VoprfServer::<CS>::new(&mut rng).unwrap();
         let server_result = server.blind_evaluate(&mut rng, &client_blind_result.message);
@@ -638,19 +587,15 @@ mod tests {
         assert_eq!(client_finalize_result, res2);
     }
 
-    fn verifiable_batch_retrieval<CS: CipherSuite>()
+    fn verifiable_batch_retrieval<CS: CipherSuite>() {
-    where
+        let mut rng = SysRng;
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
-        let mut rng = OsRng;
         let mut inputs = vec![];
         let mut client_states = vec![];
         let mut client_messages = vec![];
         let num_iterations = 10;
         for _ in 0..num_iterations {
             let mut input = [0u8; 32];
-            rng.fill_bytes(&mut input);
+            rng.try_fill_bytes(&mut input).unwrap();
             let client_blind_result = VoprfClient::<CS>::blind(&input, &mut rng).unwrap();
             inputs.push(input);
             client_states.push(client_blind_result.state);
@@ -686,19 +631,15 @@ mod tests {
         assert_eq!(client_finalize_result, res2);
     }
 
-    fn verifiable_batch_bad_public_key<CS: CipherSuite>()
+    fn verifiable_batch_bad_public_key<CS: CipherSuite>() {
-    where
+        let mut rng = SysRng;
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
-        let mut rng = OsRng;
         let mut inputs = vec![];
         let mut client_states = vec![];
         let mut client_messages = vec![];
         let num_iterations = 10;
         for _ in 0..num_iterations {
             let mut input = [0u8; 32];
-            rng.fill_bytes(&mut input);
+            rng.try_fill_bytes(&mut input).unwrap();
             let client_blind_result = VoprfClient::<CS>::blind(&input, &mut rng).unwrap();
             inputs.push(input);
             client_states.push(client_blind_result.state);
@@ -717,7 +658,7 @@ mod tests {
             .unwrap();
         let messages: Vec<_> = messages.collect();
         let wrong_pk = {
-            let dst = Dst::new::<CS, _, _>(STR_HASH_TO_GROUP, Mode::Oprf);
+            let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, Mode::Oprf);
             // Choose a group element that is unlikely to be the right public key
             CS::Group::hash_to_curve::<CS::Hash>(&[b"msg"], &dst.as_dst()).unwrap()
         };
@@ -726,18 +667,14 @@ mod tests {
         assert!(client_finalize_result.is_err());
     }
 
-    fn verifiable_bad_public_key<CS: CipherSuite>()
+    fn verifiable_bad_public_key<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = VoprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server = VoprfServer::<CS>::new(&mut rng).unwrap();
         let server_result = server.blind_evaluate(&mut rng, &client_blind_result.message);
         let wrong_pk = {
-            let dst = Dst::new::<CS, _, _>(STR_HASH_TO_GROUP, Mode::Oprf);
+            let dst = Dst::new::<CS, _>(STR_HASH_TO_GROUP, Mode::Oprf);
             // Choose a group element that is unlikely to be the right public key
             CS::Group::hash_to_curve::<CS::Hash>(&[b"msg"], &dst.as_dst()).unwrap()
         };
@@ -750,13 +687,9 @@ mod tests {
         assert!(client_finalize_result.is_err());
     }
 
-    fn verifiable_server_evaluate<CS: CipherSuite>()
+    fn verifiable_server_evaluate<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = VoprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server = VoprfServer::<CS>::new(&mut rng).unwrap();
         let server_result = server.blind_evaluate(&mut rng, &client_blind_result.message);
@@ -783,15 +716,9 @@ mod tests {
         assert!(client_finalize != server_evaluate);
     }
 
-    fn zeroize_voprf_client<CS: CipherSuite>()
+    fn zeroize_voprf_client<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ElemLen>,
-        Sum<<CS::Group as Group>::ScalarLen, <CS::Group as Group>::ElemLen>: ArrayLength<u8>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = VoprfClient::<CS>::blind(input, &mut rng).unwrap();
 
         let mut state = client_blind_result.state;
@@ -803,17 +730,9 @@ mod tests {
         assert!(message.serialize().iter().all(|&x| x == 0));
     }
 
-    fn zeroize_voprf_server<CS: CipherSuite>()
+    fn zeroize_voprf_server<CS: CipherSuite>() {
-    where
-        <CS::Hash as OutputSizeUser>::OutputSize:
-            IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ElemLen>,
-        Sum<<CS::Group as Group>::ScalarLen, <CS::Group as Group>::ElemLen>: ArrayLength<u8>,
-        <CS::Group as Group>::ScalarLen: Add<<CS::Group as Group>::ScalarLen>,
-        Sum<<CS::Group as Group>::ScalarLen, <CS::Group as Group>::ScalarLen>: ArrayLength<u8>,
-    {
         let input = b"input";
-        let mut rng = OsRng;
+        let mut rng = SysRng;
         let client_blind_result = VoprfClient::<CS>::blind(input, &mut rng).unwrap();
         let server = VoprfServer::<CS>::new(&mut rng).unwrap();
         let server_result = server.blind_evaluate(&mut rng, &client_blind_result.message);
@@ -835,6 +754,7 @@ mod tests {
     fn test_functionality() -> Result<()> {
         use p256::NistP256;
         use p384::NistP384;
+        use p521::NistP521;
 
         #[cfg(feature = "ristretto255")]
         {
@@ -868,6 +788,15 @@ mod tests {
         zeroize_voprf_client::<NistP384>();
         zeroize_voprf_server::<NistP384>();
 
+        verifiable_retrieval::<NistP521>();
+        verifiable_batch_retrieval::<NistP521>();
+        verifiable_bad_public_key::<NistP521>();
+        verifiable_batch_bad_public_key::<NistP521>();
+        verifiable_server_evaluate::<NistP521>();
+
+        zeroize_voprf_client::<NistP521>();
+        zeroize_voprf_server::<NistP521>();
+
         Ok(())
     }
 }