fn credential_request_roundtrip()

in src/serialization/tests.rs [319:373]

• 44 lines of code
• 1 McCabe index (conditional complexity)

fn credential_request_roundtrip() -> Result<(), ProtocolError> {
    fn inner<CS: CipherSuite>() -> Result<(), ProtocolError>
    where
        <OprfHash<CS> as OutputSizeUser>::OutputSize:
            IsLess<U256> + IsLessOrEqual<<OprfHash<CS> as BlockSizeUser>::BlockSize>,
        OprfHash<CS>: Hash,
        <OprfHash<CS> as CoreProxy>::Core: ProxyHash,
        <<OprfHash<CS> as CoreProxy>::Core as BlockSizeUser>::BlockSize: IsLess<U256>,
        Le<<<OprfHash<CS> as CoreProxy>::Core as BlockSizeUser>::BlockSize, U256>: NonZero,
        // CredentialRequest: KgPk + Ke1Message
        <OprfGroup<CS> as Group>::ElemLen: Add<Ke1MessageLen<CS>>,
        CredentialRequestLen<CS>: ArrayLength<u8>,
    {
        let mut rng = OsRng;
        let alpha = random_point::<CS>();
        let alpha_bytes = CS::KeGroup::serialize_pk(&alpha);

        let client_e_kp = KeyPair::<CS::KeGroup>::generate_random(&mut rng);
        let mut client_nonce = [0u8; NonceLen::USIZE];
        rng.fill_bytes(&mut client_nonce);

        let ke1m: Vec<u8> = [
            client_nonce.as_ref(),
            client_e_kp.public().to_bytes().as_ref(),
        ]
        .concat();

        let mut input = Vec::new();
        input.extend_from_slice(&alpha_bytes);
        input.extend_from_slice(&ke1m);

        let l1 = CredentialRequest::<CS>::deserialize(&input)?;
        let l1_bytes = l1.serialize();
        assert_eq!(input, *l1_bytes);

        // Assert that identity group element is rejected
        let identity = OprfGroup::<CS>::identity_elem();
        let identity_bytes = OprfGroup::<CS>::serialize_elem(identity).to_vec();

        assert!(matches!(
            CredentialRequest::<CS>::deserialize(&[identity_bytes, ke1m.to_vec()].concat()),
            Err(ProtocolError::LibraryError(InternalError::OprfError(
                voprf::Error::Deserialization,
            )))
        ));

        Ok(())
    }

    #[cfg(feature = "ristretto255")]
    inner::<Ristretto255>()?;
    inner::<P256>()?;

    Ok(())
}