from __future__ import unicode_literals
-import base64
from math import ceil
+from .compat import compat_b64decode
from .utils import bytes_to_intlist, intlist_to_bytes
BLOCK_SIZE_BYTES = 16
return decrypted_data
+def aes_cbc_encrypt(data, key, iv):
+ """
+ Encrypt with aes in CBC mode. Using PKCS#7 padding
+
+ @param {int[]} data cleartext
+ @param {int[]} key 16/24/32-Byte cipher key
+ @param {int[]} iv 16-Byte IV
+ @returns {int[]} encrypted data
+ """
+ expanded_key = key_expansion(key)
+ block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES))
+
+ encrypted_data = []
+ previous_cipher_block = iv
+ for i in range(block_count):
+ block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES]
+ remaining_length = BLOCK_SIZE_BYTES - len(block)
+ block += [remaining_length] * remaining_length
+ mixed_block = xor(block, previous_cipher_block)
+
+ encrypted_block = aes_encrypt(mixed_block, expanded_key)
+ encrypted_data += encrypted_block
+
+ previous_cipher_block = encrypted_block
+
+ return encrypted_data
+
+
def key_expansion(data):
"""
Generate key schedule
"""
NONCE_LENGTH_BYTES = 8
- data = bytes_to_intlist(base64.b64decode(data.encode('utf-8')))
+ data = bytes_to_intlist(compat_b64decode(data))
password = bytes_to_intlist(password.encode('utf-8'))
key = password[:key_size_bytes] + [0] * (key_size_bytes - len(password))
nonce = data[:NONCE_LENGTH_BYTES]
cipher = data[NONCE_LENGTH_BYTES:]
- class Counter:
+ class Counter(object):
__value = nonce + [0] * (BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES)
def next_value(self):
return plaintext
+
RCON = (0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36)
SBOX = (0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
break
return data
+
__all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']