fn try_from()

in akd/src/ecvrf/ecvrf_impl.rs [130:153]

• 20 lines of code
• 5 McCabe index (conditional complexity)

    fn try_from(bytes: &[u8]) -> std::result::Result<VRFPublicKey, Self::Error> {
        if bytes.len() != ed25519_dalek::PUBLIC_KEY_LENGTH {
            return Err(VrfError::PublicKey("Wrong length".to_string()));
        }

        let mut bits: [u8; 32] = [0u8; 32];
        bits.copy_from_slice(&bytes[..32]);

        let compressed = curve25519_dalek::edwards::CompressedEdwardsY(bits);
        let point = compressed
            .decompress()
            .ok_or_else(|| VrfError::PublicKey("Deserialization failed".to_string()))?;

        // Check if the point lies on a small subgroup. This is required
        // when using curves with a small cofactor (in ed25519, cofactor = 8).
        if point.is_small_order() {
            return Err(VrfError::PublicKey("Small subgroup".to_string()));
        }

        match ed25519_PublicKey::from_bytes(bytes) {
            Ok(result) => Ok(VRFPublicKey(result)),
            Err(sig_err) => Err(VrfError::PublicKey(format!("Signature error {}", sig_err))),
        }
    }