import crypto input = "Burning 'em, if you ain't quick and nimble\nI go crazy when I hear a cymbal" print crypto.str_to_hex(crypto.xorstring_key(input, "ICE"))
import crypto
best = ""
bestkey = ""
bestscore = 0.0
with open('data/4.txt', 'r') as f:
for line in f:
ct = crypto.hex_to_str(line.rstrip())
for k in range(256):
s = crypto.xorstring_key(ct, chr(k))
score = crypto.score_english(s)
if score > bestscore:
best = s
bestkey = k
bestscore = score
print "Key: '{}' ({}): {}".format(chr(bestkey), bestscore, best)
import crypto
# Sanity test for 'get_hamming_distance'
s1 = "this is a test"
s2 = "wokka wokka!!!"
assert crypto.get_hamming_distance(s1, s2) == 37
ct = crypto.base64_to_str(open('data/6.txt', 'r').read())
# Try to guess the keysize based on the keysize that yields the minimum hamming
# distance
keysize = min(range(2, min(len(ct)/4, 41)),
key=lambda ks: crypto.get_normalized_hamming_distance(ct, ks, n=4))
# Now break up the ciphertext into blocks on length 'keysize' and transpose so
# that we can do frequency analysis on the result.
blocks = crypto.transpose_str(ct, keysize)
key = ""
for block in blocks:
keybyte, _, _ = crypto.break_byte_key_english(block)
key += chr(keybyte)
print "Key: '{}'".format(key)
print crypto.xorstring_key(ct, key)
