def split(self, secret, deterministic=True):
if secret >= self.P:
raise ValueError("secret must be smaller than P")
prng = Prng(deterministic=deterministic)
prng.addEntropy(secret.to_bytes(512, byteorder="big"))
a = [0] * self.k
a[0] = secret
for i in range(1, self.k):
a[i] = prng.getRandomLong(512) % self.P
x = []
for i in range(self.n):
while True:
r = int(prng.getRandomLong(16))
if r != 0 and r not in x:
x += [r]
break
y = [0] * self.n
for i in range(self.n):
y[i] = Shamir.fPoly(x[i], a, self.P)
shares = []
for i in range(self.n):
shares += [(x[i], y[i])]
return shares
def test_deterministic_Prng_2_2(self):
prng = Prng(deterministic=True)
prng.addEntropy(b"entropy")
value = prng.getRandomLong(32)
expected = 1783747816
self.assertEqual(
value, expected, "Prng not deterministic (expected: %d, got: %d)" %
(expected, value))
def encode(self, share):
prng = Prng(deterministic=self.deterministic)
prng.addEntropy(share[0].to_bytes(512, byteorder="big") +
share[1].to_bytes(512, byteorder="big"))
result = b""
result += bytes([prng.getRandomLong(8) & 0xF0 | self.version])
result += bytes([prng.getRandomLong(8) & 0xF0 | self.k])
result += rawFromLong(share[0], 16)
result += rawFromLong(share[1], self.width)
return result
def genKey(label, seed=None):
prng = Prng(deterministic=True, seed=seed)
prng.addEntropy(label.encode("utf-8"))
prng.skip(64 * 100000)
return prng.getRandomBytes(32)
