no_std support (#225)

* No std implementation

* Run tests with std

* Adding wasm32-unknown-unknown target

Co-authored-by: Kevin Lewi <[email protected]>

src/group/expand.rs

@@ -6,6 +6,7 @@
 use crate::errors::{InternalPakeError, ProtocolError};
 use crate::hash::Hash;
 use crate::serialization::i2osp;
+use alloc::vec::Vec;
 use digest::{BlockInput, Digest};
 use generic_array::typenum::Unsigned;
 
@@ -42,7 +43,7 @@ pub fn expand_message_xmd<H: Hash>(
     let l_i_b_str = i2osp(len_in_bytes, 2)?;
     let msg_prime = [&z_pad, msg, &l_i_b_str, &i2osp(0, 1)?, &dst_prime].concat();
 
-    let mut b: Vec<Vec<u8>> = vec![H::digest(&msg_prime).to_vec()]; // b[0]
+    let mut b: Vec<Vec<u8>> = alloc::vec![H::digest(&msg_prime).to_vec()]; // b[0]
 
     let mut h = H::new();
     h.update(&b[0]);
@@ -76,7 +77,7 @@ mod tests {
     #[test]
     fn test_expand_message_xmd() {
         // Test vectors taken from Section K.1 of https://www.ietf.org/archive/id/draft-irtf-cfrg-hash-to-curve-10.txt
-        let test_vectors: Vec<Params> = vec![
+        let test_vectors: alloc::vec::Vec<Params> = alloc::vec![
             Params {
                 msg: "",
                 len_in_bytes: 0x20,

src/group/mod.rs

@@ -14,9 +14,9 @@ mod x25519;
 
 use crate::errors::{InternalPakeError, ProtocolError};
 use crate::hash::Hash;
+use core::ops::Mul;
 use generic_array::{ArrayLength, GenericArray};
 use rand::{CryptoRng, RngCore};
-use std::ops::Mul;
 use zeroize::Zeroize;
 
 /// A prime-order subgroup of a base field (EC, prime-order field ...). This
@@ -34,7 +34,7 @@ pub trait Group: Copy + Sized + for<'a> Mul<&'a <Self as Group>::Scalar, Output
 
     /// Generates the contextString parameter as defined in
     /// <https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-05.txt>
-    fn get_context_string(mode: u8) -> Result<Vec<u8>, ProtocolError> {
+    fn get_context_string(mode: u8) -> Result<alloc::vec::Vec<u8>, ProtocolError> {
         use crate::serialization::i2osp;
 
         Ok([i2osp(mode as usize, 1)?, i2osp(Self::SUITE_ID, 2)?].concat())

src/group/p256.rs

@@ -11,6 +11,8 @@
 use super::Group;
 use crate::errors::{InternalPakeError, ProtocolError};
 use crate::hash::Hash;
+use core::ops::{Add, Div, Mul, Neg, Sub};
+use core::str::FromStr;
 use generic_array::typenum::{U32, U33};
 use generic_array::{ArrayLength, GenericArray};
 use num_bigint::{BigInt, Sign};
@@ -24,8 +26,6 @@ use p256_::elliptic_curve::subtle::ConstantTimeEq;
 use p256_::elliptic_curve::Field;
 use p256_::{AffinePoint, EncodedPoint, ProjectivePoint};
 use rand::{CryptoRng, RngCore};
-use std::ops::{Add, Div, Mul, Neg, Sub};
-use std::str::FromStr;
 
 // https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-hash-to-curve-11#section-8.2
 // `p: 2^256 - 2^224 + 2^192 + 2^96 - 1`
@@ -411,7 +411,7 @@ mod tests {
     #[test]
     fn map_to_curve_simple_swu() {
         // Test vectors taken from https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-hash-to-curve-11#appendix-J.1.1
-        let test_vectors: Vec<Params> = vec![
+        let test_vectors = alloc::vec![
             Params {
                 msg: "",
                 px: "2c15230b26dbc6fc9a37051158c95b79656e17a1a920b11394ca91c44247d3e4",

src/group/ristretto.rs

@@ -6,6 +6,7 @@
 use super::Group;
 use crate::errors::{InternalPakeError, ProtocolError};
 use crate::hash::Hash;
+use core::convert::TryInto;
 use curve25519_dalek::{
     constants::RISTRETTO_BASEPOINT_POINT,
     ristretto::{CompressedRistretto, RistrettoPoint},
@@ -14,7 +15,6 @@ use curve25519_dalek::{
 };
 use generic_array::{typenum::U32, GenericArray};
 use rand::{CryptoRng, RngCore};
-use std::convert::TryInto;
 use subtle::ConstantTimeEq;
 
 /// The implementation of such a subgroup for Ristretto