blowfish-decrypt.py

#!/usr/bin/env python3
from Crypto.Cipher import Blowfish
from Crypto.Util.Padding import unpad
import time

# define key and IV
key = b'KEYKEYKE'
iv = b'IVIVIVIV'

size_handling = [100000, 500000, 1000000 ,5000000,10000000]

for i in size_handling:
    ciphertext = b'\xbf\x92\xfd\x9eV\xa7uU\xb7A\x87\xec_\xf0\xa7\xe7\x06k\xb5\x98\x89\xeb`\xaf2\x7f\xe3\xa2\x08z\x8f\xd9\x97\xd9$"\x9d\x15?\x05\xf0P@\x90B\xb9\x9a;' * i
    t1 = time.time()
    # create cipher object with Blowfish algorithm in CBC mode
    cipher = Blowfish.new(key, Blowfish.MODE_CBC, iv)

    # decrypt the ciphertext
    decrypted_padding = cipher.decrypt(ciphertext) # decryption
    plaintext = unpad(decrypted_padding, Blowfish.block_size) #remove padding 

    t2 = time.time()
    t3 = t2 - t1 #total time to decrypt according to file size

    print(f'time taken to decrypt: {t3} for size bytes: {i}')