"""Transposition Cipher Test
Demonstrates a unit test for the transposition encrypt and decrypt functions.
Note:
https://www.nostarch.com/crackingcodes/ (BSD Licensed)
"""
import random
import sys
from pythontutorials.books.CrackingCodesWithPython.Chapter07.transpositionEncrypt import encryptMessage
from pythontutorials.books.CrackingCodesWithPython.Chapter08.transpositionDecrypt import decryptMessage
[docs]def main():
random.seed(42) # Set the random "seed" to a static value.
for i in range(20): # Run 20 tests.
# Generate random messages to test.
# The message will have a random length:
message = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' * random.randint(4, 40)
# Convert the message string to a list to shuffle it:
message = list(message)
random.shuffle(message)
message = ''.join(message) # Convert the list back to a string.
print('Test #%s: %s..."' % (i + 1, message[:50]))
# Check all possible keys for each message:
for key in range(1, int(len(message)/2)):
encrypted = encryptMessage(key, message)
decrypted = decryptMessage(key, encrypted)
# If the decryption doesn't match the original message, display
# an error message and quit:
if message != decrypted:
print('Mismatch with key %s and message %s.' % (key, message))
print('Decrypted as: ' + decrypted)
sys.exit()
print('Transposition cipher test passed.')
# If transpositionTest.py is run (instead of imported as a module) call
# the main() function:
if __name__ == '__main__':
main()