def score_guess(guess, i, reference_i):
guess = data(guess).bytes
plain_chars = set([x for x in abc])
compare_with = [x for x in texts if len(x) > i]
reference = texts[reference_i]
return sum([
data(xor(xor(x[i:i + 1], guess), reference[i:i + 1])).ascii()
in plain_chars for x in compare_with
]) / len(compare_with)
def decode_with_keydict(keydict):
key = b''
for i in sorted(keydict.keys()):
while len(key) < i:
key += b'\x00'
key += keydict[i]
print(xor(key, data(texts[0]).bytes))
def HMAC(K, m):
Kp = data(K)
m = data(m).bytes
if len(K) < 64: Kp = data(b'\x00' * (64 - len(K)) + K)
elif len(K) > 64: Kp = data(sha1(K), 'hex')
opad = data(b'\x5c' * 64) ^ Kp
ipad = data(b'\x36' * 64) ^ Kp
return sha1(opad.bytes + data(sha1(ipad.bytes + m)).bytes)
def encrypt_one_token():
tokens = [
'MDAwMDAwTm93IHRoYXQgdGhlIHBhcnR5IGlzIGp1bXBpbmc=',
'MDAwMDAxV2l0aCB0aGUgYmFzcyBraWNrZWQgaW4gYW5kIHRoZSBWZWdhJ3MgYXJlIHB1bXBpbic=',
'MDAwMDAyUXVpY2sgdG8gdGhlIHBvaW50LCB0byB0aGUgcG9pbnQsIG5vIGZha2luZw==',
'MDAwMDAzQ29va2luZyBNQydzIGxpa2UgYSBwb3VuZCBvZiBiYWNvbg==',
'MDAwMDA0QnVybmluZyAnZW0sIGlmIHlvdSBhaW4ndCBxdWljayBhbmQgbmltYmxl',
'MDAwMDA1SSBnbyBjcmF6eSB3aGVuIEkgaGVhciBhIGN5bWJhbA==',
'MDAwMDA2QW5kIGEgaGlnaCBoYXQgd2l0aCBhIHNvdXBlZCB1cCB0ZW1wbw==',
'MDAwMDA3SSdtIG9uIGEgcm9sbCwgaXQncyB0aW1lIHRvIGdvIHNvbG8=',
'MDAwMDA4b2xsaW4nIGluIG15IGZpdmUgcG9pbnQgb2g=',
'MDAwMDA5aXRoIG15IHJhZy10b3AgZG93biBzbyBteSBoYWlyIGNhbiBibG93'
]
# token = data(tokens[0]).bytes
token = data(random.sample(tokens, 1)[0], 'b64').bytes
# iv = key[::-1]
iv = int.to_bytes(random.getrandbits(16 * 8), 16, 'big')
return (iv, CBC_encrypt(pad(token, 16), key, iv))
def cyphered_comment(comment):
comment = '"comment1=cooking%20MCs;userdata="'+data(comment).ascii().replace("=","\=").replace(";","\;")+'";comment2=%20like%20a%20pound%20of%20bacon"'
return CBC_encrypt(pad(data(comment).bytes),key)
def fake_admin():
return (data(cyphered_comment("\x00"*320))^data("\x00"*320+";admin=true;")).bytes
def is_admin(comment): # print(data(unpad(CBC_decrypt(comment,key))).bytes) return ";admin=true;" in data(unpad(CBC_decrypt(comment,key))).ascii()
def cyphered_comment(comment):
comment = '"comment1=cooking%20MCs;userdata="' + data(
comment).ascii().replace("=", "\=").replace(
";", "\;") + '";comment2=%20like%20a%20pound%20of%20bacon"'
return CTR_encrypt(pad(data(comment).bytes),
key) #counterfunction and nonce have default values
def decode_with_key(i, key):
print(xor(key, data(texts[i]).bytes)[:len(texts[i])])
def key_if(guess, i, reference_i):
return (data(guess) ^ data(
(texts[reference_i][i:]))).bytes[i:len(guess) + i]
from ctr import CTR_encrypt, counter_function
from bytestring_tools import data, chunk, xor
texts = open("cryptopals_19.txt").readlines()
texts = [data(x.strip(), 'b64').bytes for x in texts]
texts = [
CTR_encrypt(x, b"Yellow submarine", counter_function, 0) for x in texts
]
abc = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ ,!."\''
def score_guess(guess, i, reference_i):
guess = data(guess).bytes
plain_chars = set([x for x in abc])
compare_with = [x for x in texts if len(x) > i]
reference = texts[reference_i]
return sum([
data(xor(xor(x[i:i + 1], guess), reference[i:i + 1])).ascii()
in plain_chars for x in compare_with
]) / len(compare_with)
# cyphertext ^ correct_guess ^ different_cyphertext = plaintext; this estimates plaintext (badly)
def best_guesses(i, reference_i):
guesses = sorted([(score_guess(x, i, reference_i), x)
for x in abc])[::-1][:10]
return (''.join([y for x, y in guesses if x > 0.9]))
def table_of_guesses(reference_i, start=0):
def is_admin(comment):
# print(data(unpad(CBC_decrypt(comment,key))).bytes)
unencrypted = data(unpad(CBC_decrypt(comment, key, iv=key)))
verify_ascii_compliance(unencrypted.bytes)
return ";admin=true;" in unencrypted.ascii()