vigenere.py

#!/usr/bin/python
'''
  This script is for decoding vigenere ciphers. Inspired by Mr Robot
  TriBeCa challenge 2016.
  
  https://en.wikipedia.org/wiki/Vigenere_cipher

  - GI Jack, licensed under GPLv3. WIP
'''

import argparse
import string
import sys

ignore_chars = [""]

def message(message):
	print("vigenere.py:", message)

def submsg(message):
	print("\t",message)

def exit_with_error(code,message):
    print("vigenre.py: ERROR:",message, file=sys.stderr)
    sys.exit(code)
    
def warn(message):
	print("vigenre.py: WARN:",message, file=sys.stderr)

def decode_vig(key,message):
    '''decode cypher with key. Return decoded text, takes a key and message as str'''
    msg_len = len(message)
    key_len = len(key)
    # the expand the key to length of the message.
    use_key = key
    while len(use_key) < len(message):
	    use_key += key


def get_cmd_line_args():
    '''feed command line arguments through argparse '''
    parser = argparse.ArgumentParser(description='''Decode or bruteforce vigenere cipher'd text. \n
    Vigenere cipher: https://en.wikipedia.org/wiki/Vigenere_cipher '''
    ,add_help=False)
    parser.add_argument("message",help="The Encoded Message",type=str)
    parser.add_argument("-?", "--help",  help="Show This Help Message", action="help")
    method = parser.add_mutually_exclusive_group(required=True)
    method.add_argument("-f", "--keyfile",help="Try all keys in specified text file. Use one key per line",type=str)
    method.add_argument("-k", "--key",    help="Decrypt the message with specified key",type=str)
    method.add_argument("-b", "--brute",  help="Attempt to bruteforce the key",action="store_true")
    return parser.parse_args()

def main():
	cmdline_args = get_cmd_line_args()
	print(cmdline_args)

if __name__ == "__main__":
    main()