Skip to content

ed448-goldilocks: enforce RFC 8032 context length in Ed448 verification #1387

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 4 commits into
base: master
Choose a base branch
from
Open

ed448-goldilocks: enforce RFC 8032 context length in Ed448 verification #1387

Changes from 2 commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
03bcec5
Enforce RFC 8032 context length in Ed448 verification
radik878 Sep 2, 2025
c75ad76
Update ed448-goldilocks/src/sign/verifying_key.rs
radik878 Sep 14, 2025
444ac97
Update ed448-goldilocks/src/sign/verifying_key.rs
radik878 Sep 14, 2025
187f08d
Update verifying_key.rs
radik878 Sep 14, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 6 additions & 1 deletion ed448-goldilocks/src/sign/verifying_key.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -279,9 +279,14 @@ impl VerifyingKey {
return Err(SigningError::InvalidSignatureSComponent.into());
}

// RFC 8032 mandates context length <= 255 bytes. Enforce consistently with signing path.
if ctx.len() > 255 {
return Err(SigningError::PrehashedContextLength.into());
}

// SHAKE256(dom4(F, C) || R || A || PH(M), 114) -> scalar k
let mut bytes = WideEdwardsScalarBytes::default();
let ctx_len = ctx.len() as u8;
let ctx_len = u8::try_from(ctx.len()).map_err(|_| SigningError::PrehashedContextLength.into())?;
let mut reader = Shake256::default()
.chain(HASH_HEAD)
.chain([phflag])
Expand Down
Loading