def encryption_oracle(msg):
# Append 5-10 bytes randomly before and 5-10 bytes after
# 0.5 ecb 0.5 cbc
ecb = randrange(2) == 1
msg = bytes(random_aes_key()[0:randrange(10)] + msg + bytes(random_aes_key()[0:randrange(10)]))
if ecb:
return encrypt_aes_ecb(random_aes_key(), pad_pkcs7(msg, 16)), Mode.ECB
else:
return encrypt_aes_cbc(random_aes_key(), msg, 16, random_aes_key()), Mode.CBC
def encryption_oracle(msg):
secret = base64.decodebytes(
bytes(
b'Um9sbGluJyBpbiBteSA1LjAKV2l0aCBteSByYWctdG9wIGRvd24gc28gbXkg' +
b'aGFpciBjYW4gYmxvdwpUaGUgZ2lybGllcyBvbiBzdGFuZGJ5IHdhdmluZyBq'
b'dXN0IHRvIHNheSBoaQpEaWQgeW91IHN0b3A/IE5vLCBJIGp1c3QgZHJvdmUgYnkK'
))
msg = random_prefix + msg + secret
return encrypt_aes_ecb(key, pad_pkcs7(msg, 16))
def encrypt_aes_cbc(key, msg, block_size, iv):
msg = pad_pkcs7(msg, block_size)
ct_prev, ct, i = iv, [], 0
while i < len(msg) / block_size:
ct_block = encrypt_aes_ecb(
key, xor(ct_prev, msg[i * block_size:(i + 1) * block_size]))
ct.append(ct_block)
ct_prev = ct_block
i += 1
return b''.join(ct)
def encrypt(key, profile):
return encrypt_aes_ecb(key, pad_pkcs7(bytes(profile, 'utf-8'), 16))