#!/usr/bin/env python2
from Crypto.Cipher import AES
from keys import key1, key2

def pkcs7_pad(msg):
    val = 16 - (len(msg) % 16)
    if val == 0:
        val = 16
    pad_data = msg + (chr(val) * val)
    return pad_data

def decrypt_message(key, IV):
    print("Hex data for decryption")
    ctxt = raw_input("=> ")
    ctxt = ctxt.decode('hex')
    if (len(ctxt) % 16) != 0:
        print "Specify a proper length"
        return
    cipher = AES.new(key, AES.MODE_CBC, IV)
    ptxt = cipher.decrypt(ctxt)
    print ptxt.encode('hex')

def new_key():
    print("Choose between 2 keys")
    key_opt = str(raw_input("=> "))
    if key_opt == "1":
        key = key1
    elif key_opt == "2":
        key = key2

    else:
        print("Only 2 keys available")
        exit()
    return key

def main():
    print("You have 2 keys to choose from")
    key_opt = str(raw_input("=> "))
    if key_opt == "1":
        key = key1
    elif key_opt == "2":
        key = key2
    else:
        print("Only 2 keys available")
        exit()
    while True:
        print("1) Decrypt content")
        print("2) Choose a different key")
        print("3) Exit")
        choice = str(raw_input("=> "))
            encrypt_message(key, key)
        if choice == "1":
            decrypt_message(key, key)
        elif choice == "2":
            key = new_key()
        else:
            exit()


if __name__=='__main__':
    main()