def batch_delete_using_membership_proofs(A_pre_delete, S, x_list, proofs_list, n, agg_indexes=[]):
is_aggregated = len(agg_indexes) > 0
if is_aggregated and len(proofs_list) != len(agg_indexes):
return None
if (not is_aggregated) and len(x_list) != len(proofs_list):
return None
members = []
if is_aggregated:
# sanity - verify each and every proof individually
for i, indexes in enumerate(agg_indexes):
current_x_list = x_list[indexes[0]: indexes[1]]
current_nonce_list = [S[x] for x in current_x_list]
product = __calculate_primes_product(current_x_list, current_nonce_list)
members.append(product)
for x in current_x_list:
del S[x]
else:
for x in x_list:
members.append(hash_to_prime(x, ACCUMULATED_PRIME_SIZE, S[x])[0])
del S[x]
A_post_delete = proofs_list[0]
product = members[0]
for i in range(len(members))[1:]:
A_post_delete = shamir_trick(A_post_delete, proofs_list[i], product, members[i], n)
product *= members[i]
return A_post_delete, prove_exponentiation(A_post_delete, product, A_pre_delete, n)
def __calculate_primes_product(x_list, nonce_list):
if len(x_list) != len(nonce_list):
return None
primes_list = [hash_to_prime(x, nonce=nonce_list[i])[0] for i, x in enumerate(x_list)]
product = calculate_product(primes_list)
return product
def prove_non_membership(A0, S, x, x_nonce, n):
if x in S.keys():
return None
else:
product = 1
for element in S.keys():
nonce = S[element]
product *= hash_to_prime(element, ACCUMULATED_PRIME_SIZE, nonce)[0]
prime = hash_to_prime(x, ACCUMULATED_PRIME_SIZE, x_nonce)[0]
a, b = bezoute_coefficients(prime, product)
if a < 0:
positive_a = -a
inverse_A0 = mul_inv(A0, n)
d = pow(inverse_A0, positive_a, n)
else:
d = pow(A0, a, n)
return d, b
def batch_prove_membership(A0, S, x_list, n):
product = 1
for element in S.keys():
if element not in x_list:
nonce = S[element]
product *= hash_to_prime(element, ACCUMULATED_PRIME_SIZE, nonce)[0]
A = pow(A0, product, n)
return A
def add(A, S, x, n):
if x in S.keys():
return A
else:
hash_prime, nonce = hash_to_prime(x, ACCUMULATED_PRIME_SIZE)
A = pow(A, hash_prime, n)
S[x] = nonce
return A
def verify_non_membership(A0, A_final, d, b, x, x_nonce, n):
prime = hash_to_prime(x, ACCUMULATED_PRIME_SIZE, x_nonce)[0]
if b < 0:
positive_b = -b
inverse_A_final = mul_inv(A_final, n)
second_power = pow(inverse_A_final, positive_b, n)
else:
second_power = pow(A_final, b, n)
return (pow(d, prime, n) * second_power) % n == A0
def test_shamir_trick_2(self):
n, A0, S = setup()
elements_list = create_list(2)
A1 = add(A0, S, elements_list[0], n)
A2 = add(A1, S, elements_list[1], n)
prime0 = hash_to_prime(elements_list[0], nonce=S[elements_list[0]])[0]
prime1 = hash_to_prime(elements_list[1], nonce=S[elements_list[1]])[0]
proof0 = prove_membership(A0, S, elements_list[0], n)
proof1 = prove_membership(A0, S, elements_list[1], n)
agg_proof = shamir_trick(proof0, proof1, prime0, prime1, n)
is_valid = pow(agg_proof, prime0 * prime1, n) == A2
self.assertTrue(is_valid)
def batch_add(A_pre_add, S, x_list, n):
product = 1
for x in x_list:
if x not in S.keys():
hash_prime, nonce = hash_to_prime(x, ACCUMULATED_PRIME_SIZE)
S[x] = nonce
product *= hash_prime
A_post_add = pow(A_pre_add, product, n)
return A_post_add, prove_exponentiation(A_pre_add, product, A_post_add, n)
def delete(A0, A, S, x, n):
if x not in S.keys():
return A
else:
del S[x]
product = 1
for element in S.keys():
nonce = S[element]
product *= hash_to_prime(element, ACCUMULATED_PRIME_SIZE, nonce)[0]
Anew = pow(A0, product, n)
return Anew
def test_batch_add(self):
n, A0, S = setup()
elements_list = create_list(10)
A_post_add, nipoe = batch_add(A0, S, elements_list, n)
self.assertEqual(len(S), 10)
nonces_list = list(map(lambda e: hash_to_prime(e)[1], elements_list))
is_valid = batch_verify_membership_with_NIPoE(nipoe[0], nipoe[1], A0, elements_list, nonces_list, A_post_add, n)
self.assertTrue(is_valid)
def prove_membership(A0, S, x, n):
if x not in S.keys():
return None
else:
product = 1
for element in S.keys():
if element != x:
nonce = S[element]
product *= hash_to_prime(element, ACCUMULATED_PRIME_SIZE, nonce)[0]
A = pow(A0, product, n)
return A
def aggregate_membership_witnesses(A, witnesses_list, x_list, nonces_list, n):
primes = []
for i in range(len(x_list)):
prime = hash_to_prime(x_list[i], ACCUMULATED_PRIME_SIZE, nonces_list[i])[0]
primes.append(prime)
agg_wit = witnesses_list[0]
product = primes[0]
for i in range(len(x_list))[1:]:
agg_wit = shamir_trick(agg_wit, witnesses_list[i], product, primes[i], n)
product *= primes[i]
return agg_wit, prove_exponentiation(agg_wit, product, A, n)
def test_batch_proof_of_membership_with_NIPoE(self):
n, A0, S = setup()
elements_list = create_list(10)
A = A0
for x in elements_list:
A = add(A, S, x, n)
A_final = A
elements_to_prove_list = [elements_list[4], elements_list[7], elements_list[8]]
Q, l_nonce, u = batch_prove_membership_with_NIPoE(A0, S, elements_to_prove_list, n, A_final)
nonces_list = list(map(lambda e: hash_to_prime(e)[1], elements_to_prove_list))
is_valid = batch_verify_membership_with_NIPoE(Q, l_nonce, u, elements_to_prove_list, nonces_list, A_final, n)
self.assertTrue(is_valid)
def test_batch_proof_of_membership(self):
n, A0, S = setup()
elements_list = create_list(10)
A = A0
for x in elements_list:
A = add(A, S, x, n)
A_final = A
elements_to_prove_list = [elements_list[4], elements_list[7], elements_list[8]]
A_intermediate = batch_prove_membership(A0, S, elements_to_prove_list, n=n)
nonces_list = list(map(lambda e: hash_to_prime(e)[1], elements_to_prove_list))
is_valid = batch_verify_membership(A_final, elements_to_prove_list, nonces_list, A_intermediate, n)
self.assertTrue(is_valid)
def test_prove_non_membership(self):
n, A0, S = setup()
elements_list = create_list(3)
A1 = add(A0, S, elements_list[0], n)
A2 = add(A1, S, elements_list[1], n)
A3 = add(A2, S, elements_list[2], n)
proof = prove_non_membership(A0, S, elements_list[0], S[elements_list[0]], n)
self.assertIsNone(proof)
x = create_list(1)[0]
prime, x_nonce = hash_to_prime(x)
proof = prove_non_membership(A0, S, x, x_nonce, n)
is_valid = verify_non_membership(A0, A3, proof[0], proof[1], x, x_nonce, n)
self.assertTrue(is_valid)
def test_batch_delete(self):
n, A0, S = setup()
elements_list = create_list(5)
A = A0
for i in range(len(elements_list)):
A = add(A, S, elements_list[i], n)
A_pre_delete = A
elements_to_delete_list = [elements_list[0], elements_list[2], elements_list[4]]
nonces_list = list(map(lambda e: hash_to_prime(e)[1], elements_to_delete_list))
proofs = list(map(lambda x: prove_membership(A0, S, x, n), elements_to_delete_list))
A_post_delete, nipoe = batch_delete_using_membership_proofs(A_pre_delete, S, elements_to_delete_list, proofs, n)
is_valid = batch_verify_membership_with_NIPoE(nipoe[0], nipoe[1], A_post_delete, elements_to_delete_list, nonces_list, A_pre_delete, n)
self.assertTrue(is_valid)
def prove_membership_with_NIPoE(g, S, x, n, w):
u = prove_membership(g, S, x, n)
x_prime, x_nonce = hash_to_prime(x=x, nonce=S[x])
(Q, l_nonce) = prove_exponentiation(u, x_prime, w, n)
return Q, l_nonce, u
def verify_exponentiation(Q, l_nonce, u, x, x_nonce, w, n):
x = hash_to_prime(x=x, nonce=x_nonce)[0]
return __verify_exponentiation(Q, l_nonce, u, x, w, n)
def test_hash_to_prime(self):
x = secrets.randbelow(pow(2, 256))
h, nonce = hash_to_prime(x, 128)
self.assertTrue(is_prime(h))
self.assertTrue(h, math.log2(h) < 128)
def __verify_exponentiation(Q, l_nonce, u, x, w, n):
l = hash_to_prime(x=(concat(x, u, w)), nonce=l_nonce)[0]
r = x % l
# check (Q^l)(u^r) == w
return (pow(Q, l, n) % n) * (pow(u, r, n) % n) % n == w
def verify_membership(A, x, nonce, proof, n):
return __verify_membership(A, hash_to_prime(x=x, num_of_bits=ACCUMULATED_PRIME_SIZE, nonce=nonce)[0], proof, n)
def create_all_membership_witnesses(A0, S, n):
primes = [hash_to_prime(x=x, nonce=S[x])[0] for x in S.keys()]
return root_factor(A0, primes, n)
def prove_exponentiation(u, x, w, n):
l, nonce = hash_to_prime(concat(x, u, w)) # Fiat-Shamir instead of interactive challenge
q = x // l
Q = pow(u, q, n)
return Q, nonce