Function ed25519_dalek::hazmat::raw_verify_prehashed

pub fn raw_verify_prehashed<CtxDigest, MsgDigest>(
    vk: &VerifyingKey,
    prehashed_message: MsgDigest,
    context: Option<&[u8]>,
    signature: &Signature
) -> Result<(), SignatureError>
where
    MsgDigest: Digest<OutputSize = U64>,
    CtxDigest: Digest<OutputSize = U64>,

Available on crate features hazmat and digest only.

The batched Ed25519 verification check, rejecting non-canonical R values. MsgDigest is the digest used to hash the signed message. CtxDigest is the digest used to calculate the pseudorandomness needed for signing. According to the Ed25519 spec, MsgDigest = CtxDigest = Sha512.