if not args:
print "Need ciphertext as input"
usage(1)
key = chosen_keylength = None
for opt, arg in opts:
if opt == "--key":
key = arg
elif opt == "--keylength":
chosen_keylength = int(arg)
cipher = "".join(unicode(a, "utf8") for a in args)
if key:
print CryptoStuff.vigenere_decrypt(cipher, key)
else:
print "Possible key lengths (kasiski):"
print "(The English language's coincidence index is around 0.065)"
best_length = 0
goal = 0.065
for keylength in CryptoStuff.kasiski(cipher):
idx = [CryptoStuff.index_of_coincidence(chunk) for chunk in CryptoStuff.chunk_split(cipher, keylength)]
median = sorted(idx)[len(idx) / 2]
if abs(goal - best_length) > abs(goal - median):
best_length = keylength
print "Length %6d : %.4f" % (keylength, median)
if not chosen_keylength:
keylength = best_length
print "\nBest found keylength: %d" % best_length
u"U": u"10100",
u"V": u"10101",
u"W": u"10110",
u"X": u"10111",
u"Y": u"11000",
u"Z": u"11001",
u"Æ": u"11010",
u"Ø": u"11011",
u"Å": u"11100",
u" ": u"11101",
u".": u"11110",
u",": u"11111",
}
decoding = dict((encoding[k], k) for k in encoding)
keystream = CryptoStuff.lfsr_keystream((0, 1, 0, 1, 0, 1, 0, 1), (1, 1, 0, 0, 0, 1, 1, 0))
keys = ""
cipher = u"NQFTRQBNCJK,ØDXDUVZØ,EAQDX"
binary_cipher = "".join(encoding[s] for s in cipher)
print "Coded input: %s" % binary_cipher
for i in range(len(binary_cipher)):
keys += str(keystream.next())
plain_coded = tuple(xor(binary_cipher, keys))
print "Keystream used: %s" % keys
print "Coded output: %s" % "".join(str(p) for p in plain_coded)
plain = ""
for i in range(len(plain_coded) / 5):
#!/usr/bin/env python
# -*- encoding: utf-8 -*-
# Copyright Joakim Hovlandsvåg
# Licenced by GPLv3.
"""
Script for handling affine cipher cryptosystems.
"""
import sys
import CryptoStuff
# TODO: handle input better, if more functionality is needed
if __name__ == '__main__':
if len(sys.argv) <= 3:
print "Usage: affine.py a b <input-data to analyze>"
sys.exit(1)
a = int(sys.argv[1])
b = int(sys.argv[2])
for i in range(3, len(sys.argv)):
#print "%d = %s" % (i, sys.argv[i])
print CryptoStuff.affine_decrypt(unicode(sys.argv[i], 'utf-8'), a, b, 29),
