mikeecb

def xor(b1, b2):
  b = bytearray(len(b1))
  for i in range(len(b1)):
    b[i] = b1[i] ^ b2[i]
  return b

def score(s):
    freq = {}
    freq[' '] = 700000000
    freq['e'] = 390395169

mikeecb

for KEYSIZE, _ in normalized_distances[:5]:
    block_bytes = [[] for _ in range(KEYSIZE)]
    for i, byte in enumerate(b):
        block_bytes[i % KEYSIZE].append(byte)

    keys = ""
    for bbytes in block_bytes:
        keys += break_single_key_xor(bbytes)[0]

    key = bytearray(keys * len(b))

mikeecb

from Crypto.Cipher import AES

obj = AES.new("YELLOW SUBMARINE", AES.MODE_ECB)
ciphertext = "".join(list(open("7.txt", "r"))).decode("base64")
plaintext = obj.decrypt(ciphertext)
# I'm back and I'm ringin' the bell 
# A rockin' on the mike while the fly girls yell 
# In ecstasy in the back of me 
# Well that's my DJ Deshay cuttin' all them Z's 
# Hittin' hard and the girlies goin' crazy 

mikeecb

from collections import defaultdict

def repeated_blocks(buffer, block_length=16):
    reps = defaultdict(lambda: -1)
    for i in range(0, len(buffer), block_length):
        block = bytes(buffer[i:i + block_length])
        reps[block] += 1
    return sum(reps.values())

max_reps = 0

mikeecb

def pad_pkcs7(buffer, block_size):
    if len(buffer) % block_size:
        padding = (len(buffer) / block_size + 1) * block_size - len(buffer)
    else:
        padding = 0
    # Padding size must be less than a byte 
    assert 0 <= padding <= 255
    new_buffer = bytearray()
    new_buffer[:] = buffer
    new_buffer += bytearray([chr(padding)] * padding)

mikeecb

from Crypto.Cipher import AES

def xor(b1, b2):
    b = bytearray(len(b1))
    for i in range(len(b1)):
        b[i] = b1[i] ^ b2[i]
    return b

def aes_128_ecb_enc(buffer, key):
    obj = AES.new(key, AES.MODE_ECB)

mikeecb

def aes_128_ecb_enc(buffer, key):
    obj = AES.new(key, AES.MODE_ECB)
    return bytearray(obj.encrypt(bytes(buffer)))

def aes_128_ecb_dec(buffer, key):
    obj = AES.new(key, AES.MODE_ECB)
    return bytearray(obj.decrypt(bytes(buffer)))

def aes_128_cbc_enc(buffer, key, iv):
    plaintext = pad_pkcs7(buffer, AES.block_size)

mikeecb

def unpad_pkcs7(buffer):
    padding = buffer[-1]
    for i in range(len(buffer)-1, len(buffer)-padding, -1):
        if buffer[i] != buffer[-1]:
            return buffer
    new_buffer = bytearray()
    new_buffer[:] = buffer[:-padding]
    return new_buffer

mikeecb

ciphertext = bytearray("".join(list(open("10.txt", "r"))).decode("base64"))
aes_128_cbc_dec(ciphertext, key, iv)
# I'm back and I'm ringin' the bell 
# A rockin' on the mike while the fly girls yell 
# In ecstasy in the back of me 
# Well that's my DJ Deshay cuttin' all them Z's 
# Hittin' hard and the girlies goin' crazy 
# Vanilla's on the mike, man I'm not lazy. 

# I'm lettin' my drug kick in 

mikeecb

from random import randint

def random_key(length):
    key = bytearray(length)
    for i in range(length):
        key[i] = chr(randint(0, 255)) 
    return key

print repr(random_key(16))
# bytearray(b'\xe0L\xa7\xb3Z\xd6\xc0e\x87vc\xc4*\x96,\x14')