def ot_alice(socket, msgs):
"""Oblivious transfer, Alice's side.
Keyword arguments:
socket -- socket for exchanges between A and B
msgs -- a pair (msg1, msg2) to suggest to Bob
"""
# Create the prime group and send it to Bob
G = util.PrimeGroup()
socket.send_wait(G)
# OT protocol based on
# Nigel Smart’s "Cryptography Made Simple" implementation
c = G.gen_pow(G.rand_int())
h0 = socket.send_wait(c)
h1 = G.mul(c, G.inv(h0))
k = G.rand_int()
c1 = G.gen_pow(k)
e0 = util.xor_bytes(msgs[0], util.ot_hash(G.pow(h0, k), len(msgs[0])))
e1 = util.xor_bytes(msgs[1], util.ot_hash(G.pow(h1, k), len(msgs[1])))
socket.send((c1, e0, e1))
def ot_garbler(self, msgs):
"""Oblivious transfer, Alice's side.
Args:
msgs: A pair (msg1, msg2) to suggest to Bob.
"""
logging.debug("OT protocol started")
G = util.PrimeGroup()
self.socket.send_wait(G)
# OT protocol based on Nigel Smart’s "Cryptography Made Simple"
c = G.gen_pow(G.rand_int())
h0 = self.socket.send_wait(c)
h1 = G.mul(c, G.inv(h0))
k = G.rand_int()
c1 = G.gen_pow(k)
e0 = util.xor_bytes(msgs[0], self.ot_hash(G.pow(h0, k), len(msgs[0])))
e1 = util.xor_bytes(msgs[1], self.ot_hash(G.pow(h1, k), len(msgs[1])))
self.socket.send((c1, e0, e1))
logging.debug("OT protocol ended")
def __init__(self,msg1,msg2):
# sender generate a prime Group
self.G_sender = util.PrimeGroup()
# two message that needs to be sent
self.msg1 = msg1
self.msg2 = msg2
def __init__(self, choice):
# initialise the bob with his choice
self.G_rece = util.PrimeGroup()
self.x = self.G_rece.primeM1
self.choice = choice
class Alice:
# message is the message that alice send to bob, t is the number of message that bob can learn
def __init__(self):
self.ClientSocket = util.ClientSocket
def send(self, msg):
self.ClientSocket.send(msg)
def receive(self):
self.ClientSocket.receive()
port = "5556"
context = zmq.Context()
socket = context.socket(zmq.PAIR)
socket.connect("tcp://localhost:%s" % port)
print('client alice connected')
while True:
G_sender = util.PrimeGroup()
c = G_sender.rand_int()
print(type(c))
print('c is ', c)
socket.send(str(c).encode('utf8'))
msg = socket.recv()
print(msg.decode())
time.sleep(1)
import time
port = "5556"
context = zmq.Context()
socket = context.socket(zmq.PAIR)
print('bob listening')
socket.bind("tcp://*:%s" % port)
print('server bob connected')
while True:
msg = socket.recv()
print(msg.decode())
c = int(msg.decode())
G_rece = util.PrimeGroup()
x = G_rece.primeM1
print(type(x))
print('x is ', x)
g = G_rece.find_generator()
print(type(g))
print('g is ', g)
h_b = pow(g, x, 2)
h_1b = c // h_b
print(type(h_b), type(h_1b))
print('h_b is ', h_b, 'h_1b is ', h_1b)
# h0 (h_1b) is send to sender
socket.send(str(h_1b).encode('utf8'))
def __init__(self, b): # b refers to which Bob selects
self.b = b
self.G = util.PrimeGroup()
self.x = self.G.rand_int()
def __init__(self, M):
# M responds to kb0 kb1 including m0,m1
self.M = M
self.G = util.PrimeGroup()
k = self.G.rand_int()
self.c = self.G.primeM1