-__all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']
+from __future__ import unicode_literals
import base64
from math import ceil
BLOCK_SIZE_BYTES = 16
+
def aes_ctr_decrypt(data, key, counter):
"""
Decrypt with aes in counter mode
-
+
@param {int[]} data cipher
@param {int[]} key 16/24/32-Byte cipher key
@param {instance} counter Instance whose next_value function (@returns {int[]} 16-Byte block)
"""
expanded_key = key_expansion(key)
block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES))
-
- decrypted_data=[]
+
+ decrypted_data = []
for i in range(block_count):
counter_block = counter.next_value()
- block = data[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES]
- block += [0]*(BLOCK_SIZE_BYTES - len(block))
-
+ block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES]
+ block += [0] * (BLOCK_SIZE_BYTES - len(block))
+
cipher_counter_block = aes_encrypt(counter_block, expanded_key)
decrypted_data += xor(block, cipher_counter_block)
decrypted_data = decrypted_data[:len(data)]
-
+
return decrypted_data
+
def aes_cbc_decrypt(data, key, iv):
"""
Decrypt with aes in CBC mode
-
+
@param {int[]} data cipher
@param {int[]} key 16/24/32-Byte cipher key
@param {int[]} iv 16-Byte IV
"""
expanded_key = key_expansion(key)
block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES))
-
- decrypted_data=[]
+
+ decrypted_data = []
previous_cipher_block = iv
for i in range(block_count):
- block = data[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES]
- block += [0]*(BLOCK_SIZE_BYTES - len(block))
-
+ block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES]
+ block += [0] * (BLOCK_SIZE_BYTES - len(block))
+
decrypted_block = aes_decrypt(block, expanded_key)
decrypted_data += xor(decrypted_block, previous_cipher_block)
previous_cipher_block = block
decrypted_data = decrypted_data[:len(data)]
-
+
return decrypted_data
+
def key_expansion(data):
"""
Generate key schedule
-
+
@param {int[]} data 16/24/32-Byte cipher key
- @returns {int[]} 176/208/240-Byte expanded key
+ @returns {int[]} 176/208/240-Byte expanded key
"""
- data = data[:] # copy
+ data = data[:] # copy
rcon_iteration = 1
key_size_bytes = len(data)
expanded_key_size_bytes = (key_size_bytes // 4 + 7) * BLOCK_SIZE_BYTES
-
+
while len(data) < expanded_key_size_bytes:
temp = data[-4:]
temp = key_schedule_core(temp, rcon_iteration)
rcon_iteration += 1
- data += xor(temp, data[-key_size_bytes : 4-key_size_bytes])
-
+ data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes])
+
for _ in range(3):
temp = data[-4:]
- data += xor(temp, data[-key_size_bytes : 4-key_size_bytes])
-
+ data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes])
+
if key_size_bytes == 32:
temp = data[-4:]
temp = sub_bytes(temp)
- data += xor(temp, data[-key_size_bytes : 4-key_size_bytes])
-
- for _ in range(3 if key_size_bytes == 32 else 2 if key_size_bytes == 24 else 0):
+ data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes])
+
+ for _ in range(3 if key_size_bytes == 32 else 2 if key_size_bytes == 24 else 0):
temp = data[-4:]
- data += xor(temp, data[-key_size_bytes : 4-key_size_bytes])
+ data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes])
data = data[:expanded_key_size_bytes]
-
+
return data
+
def aes_encrypt(data, expanded_key):
"""
Encrypt one block with aes
-
+
@param {int[]} data 16-Byte state
- @param {int[]} expanded_key 176/208/240-Byte expanded key
+ @param {int[]} expanded_key 176/208/240-Byte expanded key
@returns {int[]} 16-Byte cipher
"""
rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1
data = xor(data, expanded_key[:BLOCK_SIZE_BYTES])
- for i in range(1, rounds+1):
+ for i in range(1, rounds + 1):
data = sub_bytes(data)
data = shift_rows(data)
if i != rounds:
data = mix_columns(data)
- data = xor(data, expanded_key[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES])
+ data = xor(data, expanded_key[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES])
return data
+
def aes_decrypt(data, expanded_key):
"""
Decrypt one block with aes
-
+
@param {int[]} data 16-Byte cipher
@param {int[]} expanded_key 176/208/240-Byte expanded key
@returns {int[]} 16-Byte state
"""
rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1
-
+
for i in range(rounds, 0, -1):
- data = xor(data, expanded_key[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES])
+ data = xor(data, expanded_key[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES])
if i != rounds:
data = mix_columns_inv(data)
data = shift_rows_inv(data)
data = sub_bytes_inv(data)
data = xor(data, expanded_key[:BLOCK_SIZE_BYTES])
-
+
return data
+
def aes_decrypt_text(data, password, key_size_bytes):
"""
Decrypt text
- The cipher key is retrieved by encrypting the first 16 Byte of 'password'
with the first 'key_size_bytes' Bytes from 'password' (if necessary filled with 0's)
- Mode of operation is 'counter'
-
+
@param {str} data Base64 encoded string
@param {str,unicode} password Password (will be encoded with utf-8)
@param {int} key_size_bytes Possible values: 16 for 128-Bit, 24 for 192-Bit or 32 for 256-Bit
@returns {str} Decrypted data
"""
NONCE_LENGTH_BYTES = 8
-
- data = bytes_to_intlist(base64.b64decode(data))
+
+ data = bytes_to_intlist(base64.b64decode(data.encode('utf-8')))
password = bytes_to_intlist(password.encode('utf-8'))
-
- key = password[:key_size_bytes] + [0]*(key_size_bytes - len(password))
+
+ 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)
-
+
nonce = data[:NONCE_LENGTH_BYTES]
cipher = data[NONCE_LENGTH_BYTES:]
-
+
class Counter:
- __value = nonce + [0]*(BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES)
+ __value = nonce + [0] * (BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES)
+
def next_value(self):
temp = self.__value
self.__value = inc(self.__value)
return temp
-
+
decrypted_data = aes_ctr_decrypt(cipher, key, Counter())
plaintext = intlist_to_bytes(decrypted_data)
-
+
return plaintext
RCON = (0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36)
0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d)
-MIX_COLUMN_MATRIX = ((0x2,0x3,0x1,0x1),
- (0x1,0x2,0x3,0x1),
- (0x1,0x1,0x2,0x3),
- (0x3,0x1,0x1,0x2))
-MIX_COLUMN_MATRIX_INV = ((0xE,0xB,0xD,0x9),
- (0x9,0xE,0xB,0xD),
- (0xD,0x9,0xE,0xB),
- (0xB,0xD,0x9,0xE))
+MIX_COLUMN_MATRIX = ((0x2, 0x3, 0x1, 0x1),
+ (0x1, 0x2, 0x3, 0x1),
+ (0x1, 0x1, 0x2, 0x3),
+ (0x3, 0x1, 0x1, 0x2))
+MIX_COLUMN_MATRIX_INV = ((0xE, 0xB, 0xD, 0x9),
+ (0x9, 0xE, 0xB, 0xD),
+ (0xD, 0x9, 0xE, 0xB),
+ (0xB, 0xD, 0x9, 0xE))
RIJNDAEL_EXP_TABLE = (0x01, 0x03, 0x05, 0x0F, 0x11, 0x33, 0x55, 0xFF, 0x1A, 0x2E, 0x72, 0x96, 0xA1, 0xF8, 0x13, 0x35,
0x5F, 0xE1, 0x38, 0x48, 0xD8, 0x73, 0x95, 0xA4, 0xF7, 0x02, 0x06, 0x0A, 0x1E, 0x22, 0x66, 0xAA,
0xE5, 0x34, 0x5C, 0xE4, 0x37, 0x59, 0xEB, 0x26, 0x6A, 0xBE, 0xD9, 0x70, 0x90, 0xAB, 0xE6, 0x31,
0x44, 0x11, 0x92, 0xd9, 0x23, 0x20, 0x2e, 0x89, 0xb4, 0x7c, 0xb8, 0x26, 0x77, 0x99, 0xe3, 0xa5,
0x67, 0x4a, 0xed, 0xde, 0xc5, 0x31, 0xfe, 0x18, 0x0d, 0x63, 0x8c, 0x80, 0xc0, 0xf7, 0x70, 0x07)
+
def sub_bytes(data):
return [SBOX[x] for x in data]
+
def sub_bytes_inv(data):
return [SBOX_INV[x] for x in data]
+
def rotate(data):
return data[1:] + [data[0]]
+
def key_schedule_core(data, rcon_iteration):
data = rotate(data)
data = sub_bytes(data)
data[0] = data[0] ^ RCON[rcon_iteration]
-
+
return data
+
def xor(data1, data2):
- return [x^y for x, y in zip(data1, data2)]
+ return [x ^ y for x, y in zip(data1, data2)]
+
def rijndael_mul(a, b):
- if(a==0 or b==0):
+ if(a == 0 or b == 0):
return 0
return RIJNDAEL_EXP_TABLE[(RIJNDAEL_LOG_TABLE[a] + RIJNDAEL_LOG_TABLE[b]) % 0xFF]
+
def mix_column(data, matrix):
data_mixed = []
for row in range(4):
data_mixed.append(mixed)
return data_mixed
+
def mix_columns(data, matrix=MIX_COLUMN_MATRIX):
data_mixed = []
for i in range(4):
- column = data[i*4 : (i+1)*4]
+ column = data[i * 4: (i + 1) * 4]
data_mixed += mix_column(column, matrix)
return data_mixed
+
def mix_columns_inv(data):
return mix_columns(data, MIX_COLUMN_MATRIX_INV)
+
def shift_rows(data):
data_shifted = []
for column in range(4):
for row in range(4):
- data_shifted.append( data[((column + row) & 0b11) * 4 + row] )
+ data_shifted.append(data[((column + row) & 0b11) * 4 + row])
return data_shifted
+
def shift_rows_inv(data):
data_shifted = []
for column in range(4):
for row in range(4):
- data_shifted.append( data[((column - row) & 0b11) * 4 + row] )
+ data_shifted.append(data[((column - row) & 0b11) * 4 + row])
return data_shifted
+
def inc(data):
- data = data[:] # copy
- for i in range(len(data)-1,-1,-1):
+ data = data[:] # copy
+ for i in range(len(data) - 1, -1, -1):
if data[i] == 255:
data[i] = 0
else:
data[i] = data[i] + 1
break
return data
+
+__all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']
Rapsys Git / youtubedl / blobdiff