from math import ceil from .compat import compat_b64decode, compat_ord, compat_pycrypto_AES from .utils import bytes_to_intlist, intlist_to_bytes if compat_pycrypto_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) 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) else: def aes_cbc_decrypt_bytes(data, key, iv): """ Decrypt bytes with AES-CBC using native implementation since pycryptodome is unavailable """ return intlist_to_bytes(aes_cbc_decrypt(*map(bytes_to_intlist, (data, key, iv)))) def aes_gcm_decrypt_and_verify_bytes(data, key, tag, nonce): """ Decrypt bytes with AES-GCM using native implementation since pycryptodome is unavailable """ return intlist_to_bytes(aes_gcm_decrypt_and_verify(*map(bytes_to_intlist, (data, key, tag, nonce)))) def unpad_pkcs7(data): return data[:-compat_ord(data[-1])] BLOCK_SIZE_BYTES = 16 def aes_ecb_encrypt(data, key, iv=None): """ Encrypt with aes in ECB mode @param {int[]} data cleartext @param {int[]} key 16/24/32-Byte cipher key @param {int[]} iv Unused for this mode @returns {int[]} encrypted data """ expanded_key = key_expansion(key) block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES)) 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)] return encrypted_data def aes_ecb_decrypt(data, key, iv=None): """ Decrypt with aes in ECB mode @param {int[]} data cleartext @param {int[]} key 16/24/32-Byte cipher key @param {int[]} iv Unused for this mode @returns {int[]} decrypted data """ expanded_key = key_expansion(key) block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES)) encrypted_data = [] for i in range(block_count): block = data[i * BLOCK_SIZE_BYTES: (i + 1) * BLOCK_SIZE_BYTES] encrypted_data += aes_decrypt(block, expanded_key) encrypted_data = encrypted_data[:len(data)] return encrypted_data def aes_ctr_decrypt(data, key, iv): """ Decrypt with aes in counter mode @param {int[]} data cipher @param {int[]} key 16/24/32-Byte cipher key @param {int[]} iv 16-Byte initialization vector @returns {int[]} decrypted data """ return aes_ctr_encrypt(data, key, iv) def aes_ctr_encrypt(data, key, iv): """ Encrypt with aes in counter mode @param {int[]} data cleartext @param {int[]} key 16/24/32-Byte cipher key @param {int[]} iv 16-Byte initialization vector @returns {int[]} encrypted data """ expanded_key = key_expansion(key) block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES)) counter = iter_vector(iv) encrypted_data = [] for i in range(block_count): counter_block = next(counter) 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) encrypted_data += xor(block, cipher_counter_block) encrypted_data = encrypted_data[:len(data)] return encrypted_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 @returns {int[]} decrypted data """ expanded_key = key_expansion(key) block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES)) 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)) 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 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 aes_gcm_decrypt_and_verify(data, key, tag, nonce): """ Decrypt with aes in GBM mode and checks authenticity using tag @param {int[]} data cipher @param {int[]} key 16-Byte cipher key @param {int[]} tag authentication tag @param {int[]} nonce IV (recommended 12-Byte) @returns {int[]} decrypted data """ # XXX: check aes, gcm param hash_subkey = aes_encrypt([0] * BLOCK_SIZE_BYTES, key_expansion(key)) if len(nonce) == 12: j0 = nonce + [0, 0, 0, 1] else: fill = (BLOCK_SIZE_BYTES - (len(nonce) % BLOCK_SIZE_BYTES)) % BLOCK_SIZE_BYTES + 8 ghash_in = nonce + [0] * fill + bytes_to_intlist((8 * len(nonce)).to_bytes(8, 'big')) j0 = ghash(hash_subkey, ghash_in) # TODO: add nonce support to aes_ctr_decrypt # nonce_ctr = j0[:12] iv_ctr = inc(j0) decrypted_data = aes_ctr_decrypt(data, key, iv_ctr + [0] * (BLOCK_SIZE_BYTES - len(iv_ctr))) pad_len = len(data) // 16 * 16 s_tag = ghash( hash_subkey, data + [0] * (BLOCK_SIZE_BYTES - len(data) + pad_len) # pad + bytes_to_intlist((0 * 8).to_bytes(8, 'big') # length of associated data + ((len(data) * 8).to_bytes(8, 'big'))) # length of data ) if tag != aes_ctr_encrypt(s_tag, key, j0): raise ValueError("Mismatching authentication tag") return decrypted_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 @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): data = sub_bytes(data) data = shift_rows(data) if i != rounds: data = list(iter_mix_columns(data, MIX_COLUMN_MATRIX)) 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]) if i != rounds: data = list(iter_mix_columns(data, MIX_COLUMN_MATRIX_INV)) 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 first 8 Bytes of decoded 'data' are the 8 high Bytes of the counter - 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(compat_b64decode(data)) password = bytes_to_intlist(password.encode('utf-8')) 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:] decrypted_data = aes_ctr_decrypt(cipher, key, nonce + [0] * (BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES)) plaintext = intlist_to_bytes(decrypted_data) 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, 0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15, 0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75, 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84, 0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF, 0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8, 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2, 0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73, 0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB, 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79, 0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08, 0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A, 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E, 0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF, 0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16) SBOX_INV = (0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, 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)) 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, 0x53, 0xF5, 0x04, 0x0C, 0x14, 0x3C, 0x44, 0xCC, 0x4F, 0xD1, 0x68, 0xB8, 0xD3, 0x6E, 0xB2, 0xCD, 0x4C, 0xD4, 0x67, 0xA9, 0xE0, 0x3B, 0x4D, 0xD7, 0x62, 0xA6, 0xF1, 0x08, 0x18, 0x28, 0x78, 0x88, 0x83, 0x9E, 0xB9, 0xD0, 0x6B, 0xBD, 0xDC, 0x7F, 0x81, 0x98, 0xB3, 0xCE, 0x49, 0xDB, 0x76, 0x9A, 0xB5, 0xC4, 0x57, 0xF9, 0x10, 0x30, 0x50, 0xF0, 0x0B, 0x1D, 0x27, 0x69, 0xBB, 0xD6, 0x61, 0xA3, 0xFE, 0x19, 0x2B, 0x7D, 0x87, 0x92, 0xAD, 0xEC, 0x2F, 0x71, 0x93, 0xAE, 0xE9, 0x20, 0x60, 0xA0, 0xFB, 0x16, 0x3A, 0x4E, 0xD2, 0x6D, 0xB7, 0xC2, 0x5D, 0xE7, 0x32, 0x56, 0xFA, 0x15, 0x3F, 0x41, 0xC3, 0x5E, 0xE2, 0x3D, 0x47, 0xC9, 0x40, 0xC0, 0x5B, 0xED, 0x2C, 0x74, 0x9C, 0xBF, 0xDA, 0x75, 0x9F, 0xBA, 0xD5, 0x64, 0xAC, 0xEF, 0x2A, 0x7E, 0x82, 0x9D, 0xBC, 0xDF, 0x7A, 0x8E, 0x89, 0x80, 0x9B, 0xB6, 0xC1, 0x58, 0xE8, 0x23, 0x65, 0xAF, 0xEA, 0x25, 0x6F, 0xB1, 0xC8, 0x43, 0xC5, 0x54, 0xFC, 0x1F, 0x21, 0x63, 0xA5, 0xF4, 0x07, 0x09, 0x1B, 0x2D, 0x77, 0x99, 0xB0, 0xCB, 0x46, 0xCA, 0x45, 0xCF, 0x4A, 0xDE, 0x79, 0x8B, 0x86, 0x91, 0xA8, 0xE3, 0x3E, 0x42, 0xC6, 0x51, 0xF3, 0x0E, 0x12, 0x36, 0x5A, 0xEE, 0x29, 0x7B, 0x8D, 0x8C, 0x8F, 0x8A, 0x85, 0x94, 0xA7, 0xF2, 0x0D, 0x17, 0x39, 0x4B, 0xDD, 0x7C, 0x84, 0x97, 0xA2, 0xFD, 0x1C, 0x24, 0x6C, 0xB4, 0xC7, 0x52, 0xF6, 0x01) RIJNDAEL_LOG_TABLE = (0x00, 0x00, 0x19, 0x01, 0x32, 0x02, 0x1a, 0xc6, 0x4b, 0xc7, 0x1b, 0x68, 0x33, 0xee, 0xdf, 0x03, 0x64, 0x04, 0xe0, 0x0e, 0x34, 0x8d, 0x81, 0xef, 0x4c, 0x71, 0x08, 0xc8, 0xf8, 0x69, 0x1c, 0xc1, 0x7d, 0xc2, 0x1d, 0xb5, 0xf9, 0xb9, 0x27, 0x6a, 0x4d, 0xe4, 0xa6, 0x72, 0x9a, 0xc9, 0x09, 0x78, 0x65, 0x2f, 0x8a, 0x05, 0x21, 0x0f, 0xe1, 0x24, 0x12, 0xf0, 0x82, 0x45, 0x35, 0x93, 0xda, 0x8e, 0x96, 0x8f, 0xdb, 0xbd, 0x36, 0xd0, 0xce, 0x94, 0x13, 0x5c, 0xd2, 0xf1, 0x40, 0x46, 0x83, 0x38, 0x66, 0xdd, 0xfd, 0x30, 0xbf, 0x06, 0x8b, 0x62, 0xb3, 0x25, 0xe2, 0x98, 0x22, 0x88, 0x91, 0x10, 0x7e, 0x6e, 0x48, 0xc3, 0xa3, 0xb6, 0x1e, 0x42, 0x3a, 0x6b, 0x28, 0x54, 0xfa, 0x85, 0x3d, 0xba, 0x2b, 0x79, 0x0a, 0x15, 0x9b, 0x9f, 0x5e, 0xca, 0x4e, 0xd4, 0xac, 0xe5, 0xf3, 0x73, 0xa7, 0x57, 0xaf, 0x58, 0xa8, 0x50, 0xf4, 0xea, 0xd6, 0x74, 0x4f, 0xae, 0xe9, 0xd5, 0xe7, 0xe6, 0xad, 0xe8, 0x2c, 0xd7, 0x75, 0x7a, 0xeb, 0x16, 0x0b, 0xf5, 0x59, 0xcb, 0x5f, 0xb0, 0x9c, 0xa9, 0x51, 0xa0, 0x7f, 0x0c, 0xf6, 0x6f, 0x17, 0xc4, 0x49, 0xec, 0xd8, 0x43, 0x1f, 0x2d, 0xa4, 0x76, 0x7b, 0xb7, 0xcc, 0xbb, 0x3e, 0x5a, 0xfb, 0x60, 0xb1, 0x86, 0x3b, 0x52, 0xa1, 0x6c, 0xaa, 0x55, 0x29, 0x9d, 0x97, 0xb2, 0x87, 0x90, 0x61, 0xbe, 0xdc, 0xfc, 0xbc, 0x95, 0xcf, 0xcd, 0x37, 0x3f, 0x5b, 0xd1, 0x53, 0x39, 0x84, 0x3c, 0x41, 0xa2, 0x6d, 0x47, 0x14, 0x2a, 0x9e, 0x5d, 0x56, 0xf2, 0xd3, 0xab, 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 key_expansion(data): """ Generate key schedule @param {int[]} data 16/24/32-Byte cipher key @returns {int[]} 176/208/240-Byte expanded key """ 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]) for _ in range(3): temp = data[-4:] 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): temp = data[-4:] data += xor(temp, data[-key_size_bytes: 4 - key_size_bytes]) data = data[:expanded_key_size_bytes] return data def iter_vector(iv): while True: yield iv iv = inc(iv) 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)] def iter_mix_columns(data, matrix): for i in (0, 4, 8, 12): for row in matrix: mixed = 0 for j in range(4): # xor is (+) and (-) mixed ^= (0 if data[i:i + 4][j] == 0 or row[j] == 0 else RIJNDAEL_EXP_TABLE[(RIJNDAEL_LOG_TABLE[data[i + j]] + RIJNDAEL_LOG_TABLE[row[j]]) % 0xFF]) yield mixed def shift_rows(data): return [data[((column + row) & 0b11) * 4 + row] for column in range(4) for row in range(4)] def shift_rows_inv(data): return [data[((column - row) & 0b11) * 4 + row] for column in range(4) for row in range(4)] def shift_block(data): data_shifted = [] bit = 0 for n in data: if bit: n |= 0x100 bit = n & 1 n >>= 1 data_shifted.append(n) return data_shifted def inc(data): 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 def block_product(block_x, block_y): # NIST SP 800-38D, Algorithm 1 if len(block_x) != BLOCK_SIZE_BYTES or len(block_y) != BLOCK_SIZE_BYTES: raise ValueError("Length of blocks need to be %d bytes" % BLOCK_SIZE_BYTES) block_r = [0xE1] + [0] * (BLOCK_SIZE_BYTES - 1) block_v = block_y[:] block_z = [0] * BLOCK_SIZE_BYTES for i in block_x: for bit in range(7, -1, -1): if i & (1 << bit): block_z = xor(block_z, block_v) do_xor = block_v[-1] & 1 block_v = shift_block(block_v) if do_xor: block_v = xor(block_v, block_r) return block_z def ghash(subkey, data): # NIST SP 800-38D, Algorithm 2 if len(data) % BLOCK_SIZE_BYTES: raise ValueError("Length of data should be %d bytes" % BLOCK_SIZE_BYTES) last_y = [0] * BLOCK_SIZE_BYTES for i in range(0, len(data), BLOCK_SIZE_BYTES): block = data[i : i + BLOCK_SIZE_BYTES] # noqa: E203 last_y = block_product(xor(last_y, block), subkey) return last_y __all__ = [ 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_cbc_decrypt_bytes', 'aes_decrypt_text', 'aes_encrypt', 'aes_gcm_decrypt_and_verify', 'aes_gcm_decrypt_and_verify_bytes', 'key_expansion', 'unpad_pkcs7', ]