Function raw_verify

pub fn raw_verify<CtxDigest>(
    vk: &VerifyingKey,
    message: &[u8],
    signature: &Signature,
) -> Result<(), SignatureError>
where
    CtxDigest: Digest<OutputSize = U64>,

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