import socket

import hashlib

import hmac

import json

import subprocess

import time

import os

from lib.Message import Message

from lib.utils import crypto_random

from lib.socket_wrapper import socket_send, socket_receive, get_client_socket

N = 0x009f4f57c0d386b90c5cf147d96466c5c7b2d154e7d32a58695191847f58f5e2ca9c28b497ae1b31d1c2507b1c489662a9d39c5b5100503888cfd7c762a7c1310d26b8ae38ad8de4ba3ff800022221c73be2da3113b4a7ba404a32a446adb9dedb2958bab3b26f2984396e1af1fc28594182b2a72de7fed99ea03e34c0d69e02db

g = 2

k = 3

I = '[email protected]'

P = 'somepassword1234'

def log_in_with_A_set(sock, A):

# C & S: Agree on N=[NIST Prime], g=2, k=3, I (email), P (password)

print "Sending N, g & k to the server."

data = json.dumps({'N': N, 'g': g, 'k': k})

socket_send(sock, data)

print ""

# C->S: Send I, A=0

print "C->S: Send I, A=0"

print "I:", I

print "A:", A

print ""

data = json.dumps({'I': I, 'A': A})

socket_send(sock, data)

values = socket_receive(sock)

for key, value in values.iteritems():

globals()[key] = value

assert salt != None

assert B != None

print 'Received variables salt and B'

print "salt:", salt

print "B:", B

print ""

# S, C: Compute string uH = SHA256(A|B), u = integer of uH

print "S, C: Compute string uH = SHA256(A|B), u = integer of uH"

u_sha256_generator = hashlib.sha256()

u_sha256_generator.update(Message().set_int(A).to_str() + Message().set_int(B).to_str())

u = int(u_sha256_generator.hexdigest(), 16)

print "u:", u

print ""

# C:

# Generate string xH=SHA256(salt|password)

# Convert xH to integer x somehow (put 0x on hexdigest)

print " Generate string xH=SHA256(salt|password)"

print " Convert xH to integer x somehow (put 0x on hexdigest)"

x_sha256_generator = hashlib.sha256()

x_sha256_generator.update(Message().set_int(salt).to_str() + P)

x = int(x_sha256_generator.hexdigest(), 16)

# Generate S = (B - k * g**x)**(a + u * x) % N

print " We know S = 0"

# buff = B - k * g**x

S = 0

print "S:", S

# Generate K = SHA256(S)

print " Generate K = SHA256(S)"

K_sha256_generator = hashlib.sha256()

K_sha256_generator.update(Message().set_int(S).to_str())

K = int(K_sha256_generator.hexdigest(), 16)

print "K:", K

print ""

# C->S: Send HMAC-SHA256(K, salt)

signature = hmac.HMAC(Message().set_int(K).to_str(), Message().set_int(salt).to_str(), hashlib.sha256).hexdigest()

data = json.dumps({'signature': signature})

socket_send(sock, data)

print "C->S: Send HMAC-SHA256(K, salt)"

print ""

values = socket_receive(sock)

for key, value in values.iteritems():

globals()[key] = value

assert response != None

if response == "OK":

print "OK: Logged in"

elif response == 'ERROR':

print "ERROR: Not logged in"

def log_loop_with_A_set(args, A):

# Start server.

print "Starting the server ..."

server_path = os.path.join('lib', 'srp_server.py')

server_logfile = os.path.join("/tmp", "srp_server.log")

with open(server_logfile, 'w+') as devnull:

server_process = subprocess.Popen(

'python {} {}'.format(server_path, str(args.port_number)),

shell=True,

stdout=devnull,

stderr=devnull)

time.sleep(2)

ret = server_process.poll()

if ret != None:

print "Server has not started correctly. Port already in use?"

exit(1)

# Get communication socket.

sock = get_client_socket(args.hostname, args.port_number)

print "Communications initialised"

print ""

try:

log_in_with_A_set(sock, A)

finally:

sock.shutdown(socket.SHUT_RDWR)

def main(args):

for A in [0, N, N**2]:

print "*" * 70

log_loop_with_A_set(args, A)

print "*" * 70

if __name__ == '__main__':

import argparse

parser = argparse.ArgumentParser(

description='Break SRP with a zero key - Challenge 35 (Set 5) of Matasano Crypto Challenge.'

)

parser.add_argument('hostname',

help='Address of the host to connect to', type=str)

parser.add_argument('port_number',

help='Port number to connect to', type=int)

args = parser.parse_args()

main(args)