def gen_triples(t, n, n_triples):
triples = [[] for _ in range(n)]
for i in range(n_triples):
a = randelement()
b = randelement()
c = a * b
a_shares = Shamir(t, n).share_secret(a)
b_shares = Shamir(t, n).share_secret(b)
c_shares = Shamir(t, n).share_secret(c)
for i in range(n):
triples[i].append(
TripleShare(a_shares[i], b_shares[i], c_shares[i]))
return triples
def test_secure_addition(): t = 2 n = 2*t+1 shamir = Shamir(t, n) s1 = randelement() s2 = randelement() answer = s1+s2 shares1 = shamir.share_secret(s1) shares2 = shamir.share_secret(s2) # Each party locally adds their share of secret 1 and 2 final_shares = [shares1[i]+shares2[i] for i in range(n)] # Check reconstructed = shamir.reconstruct_secret(final_shares[0:t+1]) assert answer == reconstructed, "reconstructed the wrong value"
def test_reconstruction(): t = 2 n = 2*t+1 shamir = Shamir(t, n) secret = randelement() shares = shamir.share_secret(secret) reconstructed = shamir.reconstruct_secret(shares[:t+1]) assert secret == reconstructed, "reconstructed the wrong value"
def test_secure_multiplication():
t = 2
n = 2 * t + 1
n_muls = 5
shamir = Shamir(t, n)
xs = [randelement() for _ in range(n_muls)]
ys = [randelement() for _ in range(n_muls)]
answers = [xs[i] * ys[i] for i in range(n_muls)]
x_sharings = [shamir.share_secret(xs[i]) for i in range(n_muls)]
y_sharings = [shamir.share_secret(ys[i]) for i in range(n_muls)]
triples = test_triple_creation(t, n, n_muls)
##
## ROUND 1
##
broadcasts = []
# Each party
for i in range(n):
# computes intermediate values (er_list) for shares to be multiplied
er_list = shamir.mul_gates_round_1([x[i] for x in x_sharings],
[y[i] for y in y_sharings],
triples[i])
# broadcasts the intermediate values to all other parties
broadcasts.append(er_list)
##
## ROUND 2
##
player_result_shares = []
# Each party
for i in range(n):
# Collects broadcasted messages and uses these intermediate values to compute result shares
result_shares = shamir.mul_gates_round_2([x[i] for x in x_sharings],
[y[i] for y in y_sharings],
broadcasts,
[t.c for t in triples[i]])
player_result_shares.append(result_shares)
# Check values
for i in range(len(answers)):
reconstructed = shamir.reconstruct_secret(
[p[i] for p in player_result_shares])
assert reconstructed == answers[i], "reconstructed the wrong value"