def test_e_add():
for i in range(5):
priv, pub = paillier.generate_keypair(128)
for j in range(5):
a = long(random.randint(0, 1000000))
b = long(random.randint(0, 1000000))
ca, cb = paillier.encrypt(pub, a), paillier.encrypt(pub, b)
cs = paillier.e_add(pub, ca, cb)
s = paillier.decrypt(priv, pub, cs)
assert a + b == s
def test_e_add():
for i in range(5):
priv, pub = paillier.generate_keypair(128)
for j in range(5):
a = long(random.randint(0, 1000000))
b = long(random.randint(0, 1000000))
ca, cb = paillier.encrypt(pub, a), paillier.encrypt(pub, b)
cs = paillier.e_add(pub, ca, cb)
s = paillier.decrypt(priv, pub, cs)
assert a + b == s
def encode_y(self, pk, C, y):
N = len(y)
T = [0] * N
R_prev = 0
for i in range(N):
D = paillier.e_add(pk, paillier.encrypt(pk, -y[i]), C[i])
F = paillier.e_add(
pk, paillier.e_add(pk, C[i], paillier.encrypt(pk, y[i])),
paillier.e_mul_const(pk, C[i], -2 * y[i]))
if i == 0:
R = F
R_prev = R
else:
R = paillier.e_add(pk, paillier.e_mul_const(pk, R_prev, 2), F)
R_prev = R
T[i] = paillier.e_add(
pk,
paillier.e_mul_const(pk, paillier.e_add_const(pk, R, -1),
random.randint(0, pk.n - 1)), D)
random.shuffle(T)
return T
def encode_y(self, pk, T, y):
scheme = self.cipher_suite.scheme
N = len(y)
C = [0 for i in range(N)]
c = 0
if scheme == "Paillier":
for i in range(N):
if y[i] == 0:
y[i] = 1
c_t = T[y[0]][0]
for k in range(1, i + 1):
c_t = paillier.e_add(pk, c_t, T[y[k]][k])
c_t = paillier.scalarize(pk, c_t)
C[c] = c_t
c += 1
y[i] = 0
for i in range(c, N):
# r = random.randint(0, pk.n-1)
C[i] = paillier.random_cipher(pk)
elif scheme == "ElGamal":
for i in range(N):
if y[i] == 0:
y[i] = 1
c_t = T[y[0]][0]
for k in range(1, i + 1):
c_t = elgamal.c_mul(pk, c_t, T[y[k]][k])
c_t = elgamal.scalarize(pk, c_t)
C[c] = c_t
c += 1
y[i] = 0
for i in range(c, N):
# r = random.randint(0, pk.n-1)
C[i] = elgamal.random_cipher(pk)
random.shuffle(C)
return C
def central_server_oblivious(x):
"""
:param
x: A 2-D array
each column correspond to the result from one subsystem
:return:
x_mean : 1-D array
the mean value across subsystems
enc_time: float
the average time for each subsystem to encrypt its result
collect_time: float
the time for the central server to compute the average
dec_time: float
the average time for each subsystem to decrypt the average send
back from the central server.
"""
# Get dimension
num_subsys = x.shape[0]
num_feature = x.shape[1]
# cx intermediate encrypted version of x
cx = []
cxn = []
# x_mean : a list, this is the returned value
x_mean = []
x_meann = []
# private key and public key, the private key is a pair of prime numbers, each about 512 bits
sk, pk = paillier.generate_keypair(512)
t0 = time.clock()
for i in range(0, num_subsys):
for j in range(0, num_feature):
if x[i,j] < 0:
x[i,j] = -x[i,j]
cxn.append(paillier.encrypt(pk, x[i,j]))
cx.append(1)
else:
cxn.append(1)
cx.append(paillier.encrypt(pk,x[i,j]))
t1 = time.clock()
enc_time = t1 - t0
# enc_time, encryption time for all sub-system, the final reported time is for each subsystem, i.e. enc_time/num_subsys
t0 = time.clock()
for i in range(0, num_subsys):
for j in range(0, num_feature):
if j == 0:
x_mean.append(cx[i*num_feature+j])
x_meann.append(cxn[i*num_feature+j])
else:
x_mean[i] = paillier.e_add(pk, x_mean[i],cx[i*num_feature+j])
x_meann[i] = paillier.e_add(pk, x_meann[i],cxn[i*num_feature+j])
t1 = time.clock()
collect_time = t1 - t0
# collect_time : time for averaging feature values among users
t0 = time.clock()
x_mean = [paillier.decrypt(sk,pk,x)/num_feature for x in x_mean]
x_meann = [paillier.decrypt(sk,pk,x)/num_feature for x in x_meann]
t1 = time.clock()
dec_time = t1 - t0
# dec_time : decryption time
x_mean = [x_mean[i] - x_meann[i] for i in range(0,len(x_mean))]
return (x_mean, enc_time/num_subsys, collect_time, dec_time)
import paillier as p priv, pub = p.generate_keypair(128) x = p.encrypt(pub, 250) y = p.encrypt(pub, 300) z = p.e_add(pub, x, y) b = p.e_sub(pub, x, y) a = p.decrypt(priv, pub, z) c = p.decrypt(priv, pub, b) print(x) print(y) print(z) print(a) print(c)
