def verify(self, vk, M, sig):
mid = cldiv(self.l_G, 8)
(Rbar, Sbar) = (sig[:mid], sig[mid:]) # TODO: bitlength(r_j)
R = Point.from_bytes(Rbar)
S = leos2ip(Sbar)
c = h_star(Rbar + M)
return R and S < r_j and self.P_g * Fr(S) == R + vk * c
def __init__(self, rand):
self.cv = find_group_hash(b'TVRandPt', rand.b(32))
self.cmu = Fq(leos2ip(rand.b(32)))
self.ephemeralKey = find_group_hash(b'TVRandPt', rand.b(32))
self.encCiphertext = rand.b(ZC_SAPLING_ENCCIPHERTEXT_SIZE)
self.outCipherText = rand.b(ZC_SAPLING_OUTCIPHERTEXT_SIZE)
self.proof = GrothProof(rand)
def __init__(self, rand):
self.cv = find_group_hash(b'TVRandPt', rand.b(32))
self.anchor = Fq(leos2ip(rand.b(32)))
self.nullifier = rand.b(32)
self.rk = Point.rand(rand)
self.proof = GrothProof(rand)
self.spendAuthSig = rand.b(64) # Invalid
def from_bytes(buf):
return Fq(leos2ip(buf), strict=True)
def crh_ivk(ak, nk):
digest = blake2s(person=b'Zcashivk')
digest.update(ak)
digest.update(nk)
ivk = digest.digest()
return leos2ip(ivk) % 2**251
def to_scalar(buf):
return Fr(leos2ip(buf))
def h_star(B):
return Fr(leos2ip(H(B)))
def private(random):
return Fr(leos2ip(random(32)))
def from_bytes(buf):
return Fq(leos2ip(buf))
