barrywhitehat / baby_jubjub_ecc Goto Github PK

In the ed25519 test example, the private string sk is used to generate the public key (see https://github.com/barryWhiteHat/baby_jubjub_ecc/blob/master/tests/ed25519.py#L172 )and also the signature but its value was not defined.

See find_group_hash @ https://github.com/daira/zcash-test-vectors/blob/master/sapling_generators.py#L31

def group_hash(D, M):
    digest = blake2s(person=D)
    digest.update(CRS)
    digest.update(M)
    p = Point.from_bytes(digest.digest())
    if not p:
        return None
    q = p * JUBJUB_COFACTOR
    if q == Point.ZERO:
        return None
    return q

def find_group_hash(D, M):
    i = 0
    while True:
        p = group_hash(D, M + bytes([i]))
        if p:
            return p
        i += 1
        assert i < 256

We use the base point
("base point " , Fq(17777552123799933955779906779655732241715742912184938656739573121738514868268), Fq(2626589144620713026669568689430873010625803728049924121243784502389097019475) )

when we should use the generator point.

('geneator :', 16540640123574156134436876038791482806971768689494387082833631921987005038935, 20819045374670962167435360035096875258406992893633759881276124905556507972311)

This should be a quick fix.

We can generate a pubic that is greater than the feild modulous as follows

        sk = 123123123
        [pub_key_x, pub_key_y] = ed.publickey(sk)
        print(pub_key_x, pub_key_y)

So we can fix this by doing

    def __int__(self):
        return(self.s%r_q)

Tho we should dig a little deeper on this and see if there is a deeper problem.

https://github.com/hyraxZK/inner_curves/blob/master/bin/find_curveparams.sage

This tool will find Montgomery and Edwards curves over a given field, however it has hard-coded restrictions on the prime modulo (for fast square root)