def generate_random(bit_size, include_negative_range, seeded, full_range):
global global_random_state
if not seeded or global_random_state is None:
global_random_state = gmpy2.random_state()
x = zero
if full_range:
x = gmpy2.mul_2exp(one, bit_size - 1)
tmp = 0
if bit_size < 33:
tmp = gmpy2.mpz_random(global_random_state, RAND_MAX)
temp = (1 << bit_size)
x = gmpy2.f_mod(tmp, temp)
if include_negative_range:
tmp = gmpy2.mul_2exp(one, bit_size - 1)
x = gmpy2.sub(x, tmp)
return x
for i in range(bit_size - 32, 0 - 1, -32):
tmp = gmpy2.mpz_random(global_random_state, RAND_MAX)
tmp = gmpy2.mul_2exp(tmp, i)
x = gmpy2.add(x, tmp)
x = gmpy2.add(x, gmpy2.mpz_random(global_random_state, RAND_MAX))
if include_negative_range:
tmp = gmpy2.mul_2exp(one, bit_size - 1)
x = gmpy2.sub(x, tmp)
return mpz(x)
def generate_secret_key(self):
tmp = mpz()
self.sk = gmpy2.mul_2exp(1, eta - 1)
random_state = gmpy2.random_state(mpz(time.time()))
i = eta - 32
while i >= 0:
tmp = gmpy2.mpz_random(random_state, RAND_MAX)
tmp = gmpy2.mul_2exp(tmp, i)
self.sk += tmp
i -= 32
self.sk += gmpy2.mpz_random(random_state, RAND_MAX)
self.sk = mpz(self.sk * 2 + 1)
def generate_x_i(sk, length):
tmp, q, r = 0, 0, 0
q = gmpy2.mul_2exp(one, length - 1)
gmpy2.random_state()
for i in range(length - 32, 0 - 1, -32):
tmp = gmpy2.get_random()
tmp = gmpy2.mul_2exp(tmp, i)
q = gmpy2.add(tmp, q)
q = gmpy2.add(q, gmpy2.get_random())
r = generate_random(rho, True, False, False)
x_i = gmpy2.mul(q, sk)
x_i = gmpy2.add(r, x_i)
return x_i
def generate_sparse_matrix(u_1, modified_secret_key, x_p):
global global_random_state
seed = mpz(time.time())
global_random_state = gmpy2.random_state(seed)
Theta_vector = [0 for _ in range(Theta)]
for i in range(1, Theta):
Theta_vector[i] = generate_random(kappa + 1, False, True, False)
modified_secret_key[0] = True
for i in range(1, Theta):
modified_secret_key[i] = False
count = theta - 1
gmpy2.random_state()
while count > 0:
index = gmpy2.mpz_random(global_random_state, RAND_MAX) % Theta
if not modified_secret_key[index]:
modified_secret_key[index] = True
count -= 1
sum_ = zero
temp = gmpy2.mul_2exp(one, kappa + 1)
for i in range(1, Theta):
if modified_secret_key[i]:
sum_ = gmpy2.add(sum_, Theta_vector[i])
sum_ %= temp
u_1 = gmpy2.sub(x_p, sum_)
if u_1 < zero:
u_1 = gmpy2.add(temp, u_1)
return mpz(seed), mpz(u_1)
def recrypt_util(self, encrypted_z, ct, PKC):
global global_random_state
u_i = [mpz() for i in range(Theta)]
u_i[0] = mpz(self.u_1)
global_random_state = gmpy2.random_state(self.seed)
for i in range(1, Theta):
u_i[i] = generate_random(kappa + 1, False, True, False)
z_i = []
den = mpz(gmpy2.mul_2exp(1, kappa))
Sum = binary_real(zero, one, n + e)
for i in range(Theta):
num = u_i[i] * ct
z_i.append(binary_real(num, den, n + e))
for i in range(Theta):
for j in range(n + 1 + e):
if j == 0:
if z_i[i].decimal == 1:
encrypted_z[i][j] = mpz(1)
else:
encrypted_z[i][j] = mpz(0)
else:
if z_i[i].value[j - 1] is True:
encrypted_z[i][j] = mpz(1)
else:
encrypted_z[i][j] = mpz(0)
def __init__(self):
self.sk = mpz(0)
self.pk = [mpz(0) for i in range(2 * beta + 1)]
self.seed = 0
self.u_1 = mpz(0)
self.modified_secret_key = [mpz(0) for i in range(Theta)]
self.encrypted_sk = [mpz(0) for i in range(Theta)]
sk_file_check = Path('secret_key.txt')
if not sk_file_check.is_file():
print('generating secret key')
sk_file = open('secret_key.txt', 'w')
self.generate_secret_key()
sk_file.write(self.sk.digits())
sk_file.close()
else:
print('loading secret key')
sk_file = open('secret_key.txt', 'r')
self.sk = mpz(sk_file.read())
sk_file.close()
print('secret key:', self.sk)
pk_file_check = Path('short_public_key.txt')
if not pk_file_check.is_file():
pk_file = open('short_public_key.txt', 'w')
self.generate_public_key()
pk_file.writelines("%s\n" % str(pk_i.digits()) for pk_i in self.pk)
print('public key generated,', len(self.pk), 'elements')
#print([str(pk_i) for pk_i in self.pk])
pk_file.close()
else:
pk_file = open('short_public_key.txt', 'r')
self.pk = [mpz(element.rstrip()) for element in pk_file.readlines()]
print('public key loaded,', len(self.pk), 'elements')
pk_file.close()
enc_sk_file_check = Path('encrypted_sk_and_seed.txt')
if not enc_sk_file_check.is_file():
x_p = mpz(gmpy2.mul_2exp(1, kappa))
x_p = mpz(gmpy2.f_div(x_p, self.sk))
self.seed, self.u_1 = generate_sparse_matrix(self.u_1, self.modified_secret_key, x_p)
for i in range(Theta):
if self.modified_secret_key[i] is True:
self.encrypted_sk[i] = self.symmetric_encryption(self.encrypted_sk[i], 1)
else:
self.encrypted_sk[i] = self.symmetric_encryption(self.encrypted_sk[i], 0)
enc_sk_file = open('encrypted_sk_and_seed.txt', 'w')
enc_sk_file.write('%s\n' % str(self.seed))
enc_sk_file.write('%s\n' % str(self.u_1))
for i in range(Theta):
enc_sk_file.write('%s\n' % str(self.encrypted_sk[i]))
enc_sk_file.close()
else:
enc_sk_file = open('encrypted_sk_and_seed.txt', 'r')
file_contents = [element.rstrip() for element in enc_sk_file.readlines()]
self.seed = int(file_contents[0])
self.u_1 = mpz(file_contents[1])
temp = mpz()
for i in range(Theta):
self.encrypted_sk[i] = mpz(file_contents[i+2])
temp = self.decrypt_bit(self.encrypted_sk[i])
if temp == 1:
self.modified_secret_key[i] = True
else:
self.modified_secret_key[i] = False
enc_sk_file.close()