Python Language
クライアントとサーバー間のソケットとメッセージの暗号化/復号化

前書き

備考

random_generator = Random.new().read
        key = RSA.generate(1024,random_generator) 
        public = key.publickey().exportKey()

eMsg = ideaEncrypt.encrypt(whole)
#converting the encrypted message to HEXADECIMAL to readable eMsg =         
eMsg.encode("hex").upper()

decoded = newmess.decode("hex")
ideaDecrypt = IDEA.new(key, IDEA.MODE_CTR, counter=lambda: key) 
dMsg = ideaDecrypt.decrypt(decoded)

サーバー側の実装

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")

クライアント側の実装

import time
import socket
import threading
import hashlib
import itertools
import sys
from Crypto import Random
from Crypto.PublicKey import RSA
from CryptoPlus.Cipher import IDEA

#animating loading
done = False
def animate():
    for c in itertools.cycle(['....','.......','..........','............']):
        if done:
            break
        sys.stdout.write('\rCONFIRMING CONNECTION TO SERVER '+c)
        sys.stdout.flush()
        time.sleep(0.1)

#public key and private key
random_generator = Random.new().read
key = RSA.generate(1024,random_generator)
public = key.publickey().exportKey()
private = key.exportKey()

#hashing the public key
hash_object = hashlib.sha1(public)
hex_digest = hash_object.hexdigest()

#Setting up socket
server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

#host and port input user
host = raw_input("Server Address To Be Connected -> ")
port = int(input("Port of The Server -> "))
#binding the address and port
server.connect((host, port))
# printing "Server Started Message"
thread_load = threading.Thread(target=animate)
thread_load.start()

time.sleep(4)
done = True

def send(t,name,key):
    mess = raw_input(name + " : ")
    key = key[:16]
    #merging the message and the name
    whole = name+" : "+mess
    ideaEncrypt = IDEA.new(key, IDEA.MODE_CTR, counter=lambda : key)
    eMsg = ideaEncrypt.encrypt(whole)
    #converting the encrypted message to HEXADECIMAL to readable
    eMsg = eMsg.encode("hex").upper()
    if eMsg != "":
        print ("ENCRYPTED MESSAGE TO SERVER-> "+eMsg)
    server.send(eMsg)
def recv(t,key):
    newmess = server.recv(1024)
    print ("\nENCRYPTED MESSAGE FROM SERVER-> " + newmess)
    key = key[:16]
    decoded = newmess.decode("hex")
    ideaDecrypt = IDEA.new(key, IDEA.MODE_CTR, counter=lambda: key)
    dMsg = ideaDecrypt.decrypt(decoded)
    print ("\n**New Message From Server**  " + time.ctime(time.time()) + " : " + dMsg + "\n")

while True:
    server.send(public)
    confirm = server.recv(1024)
    if confirm == "YES":
        server.send(hex_digest)

    #connected msg
    msg = server.recv(1024)
    en = eval(msg)
    decrypt = key.decrypt(en)
    # hashing sha1
    en_object = hashlib.sha1(decrypt)
    en_digest = en_object.hexdigest()

    print ("\n-----ENCRYPTED PUBLIC KEY AND SESSION KEY FROM SERVER-----")
    print (msg)
    print ("\n-----DECRYPTED SESSION KEY-----")
    print (en_digest)
    print ("\n-----HANDSHAKE COMPLETE-----\n")
    alais = raw_input("\nYour Name -> ")

    while True:
        thread_send = threading.Thread(target=send,args=("------Sending Message------",alais,en_digest))
        thread_recv = threading.Thread(target=recv,args=("------Recieving Message------",en_digest))
        thread_send.start()
        thread_recv.start()

        thread_send.join()
        thread_recv.join()
        time.sleep(0.5)
    time.sleep(60)
    server.close()