+import base64
from math import ceil
-from .compat import compat_b64decode, compat_ord, compat_pycrypto_AES
+from .compat import compat_ord
+from .dependencies import Cryptodome
from .utils import bytes_to_intlist, intlist_to_bytes
-if compat_pycrypto_AES:
+if Cryptodome.AES:
def aes_cbc_decrypt_bytes(data, key, iv):
""" Decrypt bytes with AES-CBC using pycryptodome """
- return compat_pycrypto_AES.new(key, compat_pycrypto_AES.MODE_CBC, iv).decrypt(data)
+ return Cryptodome.AES.new(key, Cryptodome.AES.MODE_CBC, iv).decrypt(data)
def aes_gcm_decrypt_and_verify_bytes(data, key, tag, nonce):
""" Decrypt bytes with AES-GCM using pycryptodome """
- return compat_pycrypto_AES.new(key, compat_pycrypto_AES.MODE_GCM, nonce).decrypt_and_verify(data, tag)
+ return Cryptodome.AES.new(key, Cryptodome.AES.MODE_GCM, nonce).decrypt_and_verify(data, tag)
else:
def aes_cbc_decrypt_bytes(data, key, iv):
return intlist_to_bytes(aes_gcm_decrypt_and_verify(*map(bytes_to_intlist, (data, key, tag, nonce))))
+def aes_cbc_encrypt_bytes(data, key, iv, **kwargs):
+ return intlist_to_bytes(aes_cbc_encrypt(*map(bytes_to_intlist, (data, key, iv)), **kwargs))
+
+
+BLOCK_SIZE_BYTES = 16
+
+
def unpad_pkcs7(data):
return data[:-compat_ord(data[-1])]
-BLOCK_SIZE_BYTES = 16
+def pkcs7_padding(data):
+ """
+ PKCS#7 padding
+
+ @param {int[]} data cleartext
+ @returns {int[]} padding data
+ """
+
+ remaining_length = BLOCK_SIZE_BYTES - len(data) % BLOCK_SIZE_BYTES
+ return data + [remaining_length] * remaining_length
+
+
+def pad_block(block, padding_mode):
+ """
+ Pad a block with the given padding mode
+ @param {int[]} block block to pad
+ @param padding_mode padding mode
+ """
+ padding_size = BLOCK_SIZE_BYTES - len(block)
+
+ PADDING_BYTE = {
+ 'pkcs7': padding_size,
+ 'iso7816': 0x0,
+ 'whitespace': 0x20,
+ 'zero': 0x0,
+ }
+
+ if padding_size < 0:
+ raise ValueError('Block size exceeded')
+ elif padding_mode not in PADDING_BYTE:
+ raise NotImplementedError(f'Padding mode {padding_mode} is not implemented')
+
+ if padding_mode == 'iso7816' and padding_size:
+ block = block + [0x80] # NB: += mutates list
+ padding_size -= 1
+
+ return block + [PADDING_BYTE[padding_mode]] * padding_size
def aes_ecb_encrypt(data, key, iv=None):
"""
- Encrypt with aes in ECB mode
+ Encrypt with aes in ECB mode. Using PKCS#7 padding
@param {int[]} data cleartext
@param {int[]} key 16/24/32-Byte cipher key
encrypted_data = []
for i in range(block_count):
block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES]
- encrypted_data += aes_encrypt(block, expanded_key)
- encrypted_data = encrypted_data[:len(data)]
+ encrypted_data += aes_encrypt(pkcs7_padding(block), expanded_key)
return encrypted_data
return decrypted_data
-def aes_cbc_encrypt(data, key, iv):
+def aes_cbc_encrypt(data, key, iv, *, padding_mode='pkcs7'):
"""
- Encrypt with aes in CBC mode. Using PKCS#7 padding
+ Encrypt with aes in CBC mode
@param {int[]} data cleartext
@param {int[]} key 16/24/32-Byte cipher key
@param {int[]} iv 16-Byte IV
+ @param padding_mode Padding mode to use
@returns {int[]} encrypted data
"""
expanded_key = key_expansion(key)
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
+ block = pad_block(block, padding_mode)
+
mixed_block = xor(block, previous_cipher_block)
encrypted_block = aes_encrypt(mixed_block, expanded_key)
"""
NONCE_LENGTH_BYTES = 8
- data = bytes_to_intlist(compat_b64decode(data))
- password = bytes_to_intlist(password.encode('utf-8'))
+ data = bytes_to_intlist(base64.b64decode(data))
+ password = bytes_to_intlist(password.encode())
key = password[:key_size_bytes] + [0] * (key_size_bytes - len(password))
key = aes_encrypt(key[:BLOCK_SIZE_BYTES], key_expansion(key)) * (key_size_bytes // BLOCK_SIZE_BYTES)
__all__ = [
- 'aes_ctr_decrypt',
'aes_cbc_decrypt',
'aes_cbc_decrypt_bytes',
+ 'aes_ctr_decrypt',
'aes_decrypt_text',
- 'aes_encrypt',
+ 'aes_decrypt',
+ 'aes_ecb_decrypt',
'aes_gcm_decrypt_and_verify',
'aes_gcm_decrypt_and_verify_bytes',
+
+ 'aes_cbc_encrypt',
+ 'aes_cbc_encrypt_bytes',
+ 'aes_ctr_encrypt',
+ 'aes_ecb_encrypt',
+ 'aes_encrypt',
+
'key_expansion',
+ 'pad_block',
+ 'pkcs7_padding',
'unpad_pkcs7',
]