fn test_repudiation_dalek()

in src/main.rs [1247:1293]

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

    fn test_repudiation_dalek() {
        // Pick a random Scalar
        let mut rng = new_rng();
        let mut scalar_bytes = [0u8; 32];
        rng.fill_bytes(&mut scalar_bytes);
        let s = Scalar::from_bytes_mod_order(scalar_bytes);
        debug_assert!(s.is_canonical());
        debug_assert!(s != Scalar::zero());

        let r0 = s * ED25519_BASEPOINT_POINT;
        // Pick a torsion point of order 2
        let pub_key = deserialize_point(&EIGHT_TORSION[4]).unwrap();
        let r = r0 + pub_key.neg();

        let message1 = b"Send 100 USD to Alice";
        let message2 = b"Send 100000 USD to Alice";

        debug_assert!(
            (pub_key.neg() + compute_hram(message1, &pub_key, &r) * pub_key).is_identity()
        );
        debug_assert!(
            (pub_key.neg() + compute_hram(message2, &pub_key, &r) * pub_key).is_identity()
        );

        debug_assert!(verify_cofactored(message1, &pub_key, &(r, s)).is_ok());
        debug_assert!(verify_cofactorless(message1, &pub_key, &(r, s)).is_ok());
        debug_assert!(verify_cofactored(message2, &pub_key, &(r, s)).is_ok());
        debug_assert!(verify_cofactorless(message2, &pub_key, &(r, s)).is_ok());

        println!(
            "Small pk breaks non-repudiation:\n\
             \"pub_key\": \"{}\",\n\
             \"signature\": \"{}\",\n\
             \"message1\": \"{}\",\n\
             \"message2\": \"{}\"",
            hex::encode(&pub_key.compress().as_bytes()),
            hex::encode(&serialize_signature(&r, &s)),
            hex::encode(&message1),
            hex::encode(&message2),
        );

        let signature = serialize_signature(&r, &s);
        let pk = PublicKey::from_bytes(&pub_key.compress().as_bytes()[..]).unwrap();
        let sig = Signature::try_from(&signature[..]).unwrap();
        debug_assert!(pk.verify(message1, &sig).is_ok());
        debug_assert!(pk.verify(message2, &sig).is_ok());
    }