fn ke2_message_roundtrip()

in src/serialization/tests.rs [601:641]

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

fn ke2_message_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,
    {
        let mut rng = OsRng;

        let server_e_kp = KeyPair::<CS::KeGroup>::generate_random(&mut rng);
        let mut mac = Output::<OprfHash<CS>>::default();
        rng.fill_bytes(&mut mac);
        let mut server_nonce = vec![0u8; NonceLen::USIZE];
        rng.fill_bytes(&mut server_nonce);

        let ke2m: Vec<u8> = [
            server_nonce.as_slice(),
            server_e_kp.public().to_bytes().as_ref(),
            &mac,
        ]
        .concat();

        let reg =
            <CS::KeyExchange as KeyExchange<OprfHash<CS>, CS::KeGroup>>::KE2Message::from_bytes(
                &ke2m,
            )?;
        let reg_bytes = reg.to_bytes();
        assert_eq!(*reg_bytes, ke2m);

        Ok(())
    }

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

    Ok(())
}