Example
import socket
import hashlib
import os
import time
import itertools
import threading
import sys
import Crypto.Cipher.AES as AES
from Crypto.PublicKey import RSA
from CryptoPlus.Cipher import IDEA
#server address and port number input from admin
host= raw_input("Server Address - > ")
port = int(input("Port - > "))
#boolean for checking server and port
check = False
done = False
def animate():
for c in itertools.cycle(['....','.......','..........','............']):
if done:
break
sys.stdout.write('\rCHECKING IP ADDRESS AND NOT USED PORT '+c)
sys.stdout.flush()
time.sleep(0.1)
sys.stdout.write('\r -----SERVER STARTED. WAITING FOR CLIENT-----\n')
try:
#setting up socket
server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
server.bind((host,port))
server.listen(5)
check = True
except BaseException:
print "-----Check Server Address or Port-----"
check = False
if check is True:
# server Quit
shutdown = False
# printing "Server Started Message"
thread_load = threading.Thread(target=animate)
thread_load.start()
time.sleep(4)
done = True
#binding client and address
client,address = server.accept()
print ("CLIENT IS CONNECTED. CLIENT'S ADDRESS ->",address)
print ("\n-----WAITING FOR PUBLIC KEY & PUBLIC KEY HASH-----\n")
#client's message(Public Key)
getpbk = client.recv(2048)
#conversion of string to KEY
server_public_key = RSA.importKey(getpbk)
#hashing the public key in server side for validating the hash from client
hash_object = hashlib.sha1(getpbk)
hex_digest = hash_object.hexdigest()
if getpbk != "":
print (getpbk)
client.send("YES")
gethash = client.recv(1024)
print ("\n-----HASH OF PUBLIC KEY----- \n"+gethash)
if hex_digest == gethash:
# creating session key
key_128 = os.urandom(16)
#encrypt CTR MODE session key
en = AES.new(key_128,AES.MODE_CTR,counter = lambda:key_128)
encrypto = en.encrypt(key_128)
#hashing sha1
en_object = hashlib.sha1(encrypto)
en_digest = en_object.hexdigest()
print ("\n-----SESSION KEY-----\n"+en_digest)
#encrypting session key and public key
E = server_public_key.encrypt(encrypto,16)
print ("\n-----ENCRYPTED PUBLIC KEY AND SESSION KEY-----\n"+str(E))
print ("\n-----HANDSHAKE COMPLETE-----")
client.send(str(E))
while True:
#message from client
newmess = client.recv(1024)
#decoding the message from HEXADECIMAL to decrypt the ecrypted version of the message only
decoded = newmess.decode("hex")
#making en_digest(session_key) as the key
key = en_digest[:16]
print ("\nENCRYPTED MESSAGE FROM CLIENT -> "+newmess)
#decrypting message from the client
ideaDecrypt = IDEA.new(key, IDEA.MODE_CTR, counter=lambda: key)
dMsg = ideaDecrypt.decrypt(decoded)
print ("\n**New Message** "+time.ctime(time.time()) +" > "+dMsg+"\n")
mess = raw_input("\nMessage To Client -> ")
if mess != "":
ideaEncrypt = IDEA.new(key, IDEA.MODE_CTR, counter=lambda : key)
eMsg = ideaEncrypt.encrypt(mess)
eMsg = eMsg.encode("hex").upper()
if eMsg != "":
print ("ENCRYPTED MESSAGE TO CLIENT-> " + eMsg)
client.send(eMsg)
client.close()
else:
print ("\n-----PUBLIC KEY HASH DOESNOT MATCH-----\n")
