import socket,time

import time

import datetime

from Crypto.Hash import SHA512

from Crypto.PublicKey import RSA

from Crypto import Random

s = socket.socket()

host = socket.gethostname()

port = 1274

s.connect((host, port))

'''receive public key from server'''

import cPickle

hashofpuk=s.recv(1024)

s.send('ok')

Picklekey=s.recv(1024)

if hashofpuk!=SHA512.new(Picklekey).hexdigest():

s.send('1')

s.close()

print 'Public key not valid'

exit(0)

print 'public_key valid'

public_key=cPickle.loads(Picklekey)

s.send('2')

'''convert file into hash file at client side'''

fname = 'r.pdf'

import hashlib

BLOCKSIZE=65536

h=hashlib.sha512()

with open(fname,'rb') as f:

buf= f.read(BLOCKSIZE)

while len(buf)>0:

h.update(buf)

buf=f.read(BLOCKSIZE)

h1 = h.hexdigest()

#print 'h1',h1

'''Now send the hashed file to Timestamping Server for timestamping'''

s.send(h1)

'''receive time stamp and signature from TSS'''

st=s.recv(1024)

s.send('client : time stamp received ok')

ff=s.recv(1024)

ss=ff

while len(ff)==1024:

ff=s.recv(1024)

ss+=ff

print 'client:receiving signature from server.....\n'

print 'client:received signature\n'

signature=(long(ss),)

'''now add the signature and timestamp to the new text file for

verification'''

f=open(fname.split('.')[0]+'signature.txt','w')

f.write(ss+'\n'+st)

f.close()

'''timestamping done............'''

print 'client:doc timestamped'

'''wait for modifying the document'''

time.sleep(10)

'''verify at client side'''

f=open(fname.split('.')[0]+'signature.txt','rb')

lines=f.readlines()

f.close()

sig=(long(lines[0][0:-1]),)

stt=lines[1]

hh=hashlib.sha512()

with open(fname,'rb') as f1:

buf= f1.read(BLOCKSIZE)

while len(buf)>0:

hh.update(buf)

buf=f1.read(BLOCKSIZE)

h11 = hh.hexdigest()

h22=SHA512.new(h11+stt).hexdigest()

print 'verified:',public_key.verify(h22, sig)

s.close()