def test_run(plaintext_len, key_len, key=""):
# generate plaintext
random_start = randint(0, len(english_text) - plaintext_len - 1)
plaintext = english_text[random_start:random_start + plaintext_len]
# generate key
if key == "":
key = "".join(ca.to_char(randint(0, 25)) for i in xrange(key_len))
#print 'Random key:', key
# apply encryption and decryption
#print "plaintext length:", plaintext_len, ", key length:", key_len
ciphertext = ca.translate_vigenere(plaintext, key, 0)
key_guesses = ca.break_vigenere(ciphertext,
key_len_max_try,
num_key_guesses=num_key_guesses,
num_answers=1,
max_best_shifts=max_best_shifts,
num_key_lengths=num_key_lengths)
key_guess = key_guesses[0]
score = 0.0
plaintext_guess = ca.translate_vigenere(ciphertext, key_guess, 1)
# evaluate result of key guess
if key_guess == key:
#print " perfect match!"
score = 1.0
else:
if len(key_guess) == len(key):
# calculate score of revealed key
score = 0.0
for (i, symbol) in enumerate(key_guess):
if symbol == key[i]:
score += 1
score /= float(len(key))
#print " Length is correct, key is recovered %d/%d" % (key_score, len(key))
elif len(key_guess) % len(key) == 0:
#print " Multiple of the key lenght: %d instead of %d" % (len(key_guess), len(key))
pass
else:
score = 0.0
# calculate score over whole encrypted plaintext
#score = 0.0
#for (i, symbol) in enumerate(plaintext_guess):
# if symbol == plaintext[i]:
# score += 1
#score /= float(len(plaintext))
#print " score:", score
return score
def break_vigenere(ciphertexts):
options = dict(feathermodules.current_options)
results = []
for i, sample in enumerate(ciphertexts):
keys = ca.break_vigenere(sample,
int(options['key_length_scan_range']),
num_answers=int(options['num_answers']),
max_best_shifts=int(options['num_best_shifts']),
num_key_lengths=int(options['num_key_lengths']),
num_key_guesses=int(options['num_key_guesses']),
coefficient_char_deviation=float(options['coefficient_char_deviation']),
coefficient_word_count=float(options['coefficient_word_count']))
for key in keys:
results.append('Key found for sample %d: "%s". Decrypts to: %s' % (i+1, key, ca.translate_vigenere(sample, key, decrypt=True)))
print '\n'.join(results)
return results
def break_vigenere(ciphertexts):
options = dict(feathermodules.current_options)
results = []
for i, sample in enumerate(ciphertexts):
keys = ca.break_vigenere(
sample,
int(options['key_length_scan_range']),
num_answers=int(options['num_answers']),
max_best_shifts=int(options['num_best_shifts']),
num_key_lengths=int(options['num_key_lengths']),
num_key_guesses=int(options['num_key_guesses']),
coefficient_char_deviation=float(
options['coefficient_char_deviation']),
coefficient_word_count=float(options['coefficient_word_count']))
for key in keys:
results.append(
'Key found for sample %d: "%s". Decrypts to: %s' %
(i + 1, key, ca.translate_vigenere(sample, key, decrypt=True)))
return '\n'.join(results)
import cryptanalib as ca
ct = 'XUEGTZFZARLMOWPAQRNUPLQKWPRJABVURBFBAWYEEYPILJRZMPCJAPRXANSGZZZAPNTFOJLRIBNCLBGOWGABWJRXXVASZCAJEADVDMQGQRTBWKVVLRRETAPZSFWJEKUHIGWFPVPOTUESLTCNEOEUDIYHIETJDALYXRMPYTLYAVTDSMQGPCHBMMGYESTFCARBIEAMHWEJWNNEDEVZGUETHMEKMADJNIGKHOYXCQGORTTIPTRZXRRPQBUKGBRSPACURQIORIYVLNBFEQAZLRCJAPRXXRXU'
real_pt = 'THEFIRSTWELLDOCUMENTEDDESCRIPTIONOFAPOLYALPHABETICCIPHERWASFORMULATEDBYLEONBATTISTAALBERTIAROUNDANDUSEDAMETALCIPHERDISCTOSWITCHBETWEENCIPHERALPHABETSALBERTISSYSTEMONLYSWITCHEDALPHABETSAFTERSEVERALWORDSANDSWITCHESWEREINDICATEDBYWRITINGTHELETTEROFTHECORRESPONDINGALPHABETINTHECIPHERTEXT'
print 'Testing vigenere solver...'
key = ca.break_vigenere(ct, 11)[0]
if real_pt != ca.translate_vigenere(ct, key, decrypt=True):
raise Exception('Failed to break vigenere.')
import cryptanalib as ca
ct = 'XUEGTZFZARLMOWPAQRNUPLQKWPRJABVURBFBAWYEEYPILJRZMPCJAPRXANSGZZZAPNTFOJLRIBNCLBGOWGABWJRXXVASZCAJEADVDMQGQRTBWKVVLRRETAPZSFWJEKUHIGWFPVPOTUESLTCNEOEUDIYHIETJDALYXRMPYTLYAVTDSMQGPCHBMMGYESTFCARBIEAMHWEJWNNEDEVZGUETHMEKMADJNIGKHOYXCQGORTTIPTRZXRRPQBUKGBRSPACURQIORIYVLNBFEQAZLRCJAPRXXRXU'
real_pt = 'THEFIRSTWELLDOCUMENTEDDESCRIPTIONOFAPOLYALPHABETICCIPHERWASFORMULATEDBYLEONBATTISTAALBERTIAROUNDANDUSEDAMETALCIPHERDISCTOSWITCHBETWEENCIPHERALPHABETSALBERTISSYSTEMONLYSWITCHEDALPHABETSAFTERSEVERALWORDSANDSWITCHESWEREINDICATEDBYWRITINGTHELETTEROFTHECORRESPONDINGALPHABETINTHECIPHERTEXT'
print 'Testing vigenere solver...'
key = ca.break_vigenere(ct, 11)[0]
if real_pt != ca.translate_vigenere(ct, key, decrypt=True):
raise Exception('Failed to break vigenere.')