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Update VOPRF to draft 19 (#307)

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This commit is contained in:
daxpedda
2023-03-04 20:31:07 -08:00
committed by GitHub
parent 5400128833
commit c255364ca0
11 changed files with 344 additions and 352 deletions
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src/key_exchange/group/mod.rs
+11 -20
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@@ -14,9 +14,9 @@ mod elliptic_curve;
pub mod ristretto255;
use digest::core_api::BlockSizeUser;
use digest::{Digest, OutputSizeUser};
use digest::{FixedOutput, HashMarker, OutputSizeUser};
use generic_array::sequence::Concat;
use generic_array::typenum::{IsLess, IsLessOrEqual, U11, U256};
use generic_array::typenum::{IsLess, IsLessOrEqual, U256};
use generic_array::{ArrayLength, GenericArray};
use rand::{CryptoRng, RngCore};
use zeroize::Zeroize;
@@ -48,9 +48,9 @@ pub trait KeGroup {
/// # Errors
/// [`InternalError::HashToScalar`] if the `input` is empty or longer then
/// [`u16::MAX`].
fn hash_to_scalar<H>(input: &[&[u8]], dst: &[u8]) -> Result<Self::Sk, InternalError>
fn hash_to_scalar<H>(input: &[&[u8]], dst: &[&[u8]]) -> Result<Self::Sk, InternalError>
where
H: Digest + BlockSizeUser,
H: BlockSizeUser + Default + FixedOutput + HashMarker,
H::OutputSize: IsLess<U256> + IsLessOrEqual<H::BlockSize>;
/// Corresponds to the DeriveAuthKeyPair() function defined in
@@ -67,8 +67,11 @@ pub trait KeGroup {
<CS::Hash as OutputSizeUser>::OutputSize:
IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
{
let context_string = create_context_string::<CS>(voprf::Mode::Oprf);
let dst = GenericArray::from(STR_DERIVE_KEYPAIR).concat(context_string);
let dst_1 = GenericArray::from(STR_DERIVE_KEYPAIR)
.concat(STR_OPRF.into())
.concat([voprf::Mode::Oprf.to_u8()].into())
.concat([b'-'].into());
let dst_2 = CS::ID.as_bytes();
let info_len = i2osp_2(info.len())
.map_err(|_| InternalError::OprfError(voprf::Error::DeriveKeyPair))?;
@@ -79,7 +82,7 @@ pub trait KeGroup {
// || contextString)
let sk_s = Self::hash_to_scalar::<CS::Hash>(
&[seed, &info_len, info, &counter.to_be_bytes()],
&dst,
&[&dst_1, dst_2],
)
.map_err(|_| InternalError::OprfError(voprf::Error::DeriveKeyPair))?;
@@ -110,21 +113,9 @@ pub trait KeGroup {
// Helper functions used to compute DeriveAuthKeyPair() (taken from the voprf
// crate)
const STR_VOPRF: [u8; 8] = *b"VOPRF10-";
const STR_OPRF: [u8; 7] = *b"OPRFV1-";
const STR_DERIVE_KEYPAIR: [u8; 13] = *b"DeriveKeyPair";
/// Generates the contextString parameter as defined in
/// <https://datatracker.ietf.org/doc/draft-irtf-cfrg-voprf/>
fn create_context_string<CS: voprf::CipherSuite>(mode: voprf::Mode) -> GenericArray<u8, U11>
where
<CS::Hash as OutputSizeUser>::OutputSize:
IsLess<U256> + IsLessOrEqual<<CS::Hash as BlockSizeUser>::BlockSize>,
{
GenericArray::from(STR_VOPRF)
.concat([mode.to_u8()].into())
.concat(CS::ID.to_be_bytes().into())
}
fn i2osp_2(input: usize) -> Result<[u8; 2], InternalError> {
u16::try_from(input)
.map(|input| input.to_be_bytes())