diff --git a/README.md b/README.md index 6f634f0..0917572 100755 --- a/README.md +++ b/README.md @@ -377,7 +377,8 @@ projects: - [PyCA/cryptography](https://github.com/pyca/cryptography), *BSD License* - [Pure-25519](https://github.com/warner/python-pure25519) by [Brian Warner](https://github.com/warner), *MIT License* - [Pysha2](https://github.com/thomdixon/pysha2) by [Thom Dixon](https://github.com/thomdixon), *MIT License* -- [Python-AES](https://github.com/orgurar/python-aes) by [Or Gur Arie](https://github.com/orgurar), *MIT License* +- [Python AES-128](https://github.com/orgurar/python-aes) by [Or Gur Arie](https://github.com/orgurar), *MIT License* +- [Python AES-256](https://github.com/boppreh/aes) by [BoppreH](https://github.com/boppreh), *MIT License* - [Curve25519.py](https://gist.github.com/nickovs/cc3c22d15f239a2640c185035c06f8a3#file-curve25519-py) by [Nicko van Someren](https://gist.github.com/nickovs), *Public Domain* - [I2Plib](https://github.com/l-n-s/i2plib) by [Viktor Villainov](https://github.com/l-n-s) - [PySerial](https://github.com/pyserial/pyserial) by Chris Liechti, *BSD License* diff --git a/RNS/Cryptography/AES.py b/RNS/Cryptography/AES.py index f3130b4..9025ab7 100644 --- a/RNS/Cryptography/AES.py +++ b/RNS/Cryptography/AES.py @@ -32,7 +32,8 @@ import RNS.Cryptography.Provider as cp import RNS.vendor.platformutils as pu if cp.PROVIDER == cp.PROVIDER_INTERNAL: - from .aes import AES + from .aes import AES128 + from .aes import AES256 elif cp.PROVIDER == cp.PROVIDER_PYCA: from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes @@ -44,7 +45,7 @@ class AES_128_CBC: def encrypt(plaintext, key, iv): if len(key) != 16: raise ValueError(f"Invalid key length {len(key)*8} for {self}") if cp.PROVIDER == cp.PROVIDER_INTERNAL: - cipher = AES(key) + cipher = AES128(key) return cipher.encrypt(plaintext, iv) elif cp.PROVIDER == cp.PROVIDER_PYCA: @@ -61,7 +62,7 @@ class AES_128_CBC: def decrypt(ciphertext, key, iv): if len(key) != 16: raise ValueError(f"Invalid key length {len(key)*8} for {self}") if cp.PROVIDER == cp.PROVIDER_INTERNAL: - cipher = AES(key) + cipher = AES128(key) return cipher.decrypt(ciphertext, iv) elif cp.PROVIDER == cp.PROVIDER_PYCA: @@ -79,8 +80,8 @@ class AES_256_CBC: def encrypt(plaintext, key, iv): if len(key) != 32: raise ValueError(f"Invalid key length {len(key)*8} for {self}") if cp.PROVIDER == cp.PROVIDER_INTERNAL: - cipher = AES(key) - return cipher.encrypt(plaintext, iv) + cipher = AES256(key) + return cipher.encrypt_cbc(plaintext, iv) elif cp.PROVIDER == cp.PROVIDER_PYCA: if not pu.cryptography_old_api(): @@ -96,8 +97,8 @@ class AES_256_CBC: def decrypt(ciphertext, key, iv): if len(key) != 32: raise ValueError(f"Invalid key length {len(key)*8} for {self}") if cp.PROVIDER == cp.PROVIDER_INTERNAL: - cipher = AES(key) - return cipher.decrypt(ciphertext, iv) + cipher = AES256(key) + return cipher.decrypt_cbc(ciphertext, iv) elif cp.PROVIDER == cp.PROVIDER_PYCA: if not pu.cryptography_old_api(): diff --git a/RNS/Cryptography/aes/__init__.py b/RNS/Cryptography/aes/__init__.py index 60e1669..f747978 100644 --- a/RNS/Cryptography/aes/__init__.py +++ b/RNS/Cryptography/aes/__init__.py @@ -1 +1,2 @@ -from .aes import AES \ No newline at end of file +from .aes128 import AES128 +from .aes256 import AES256 \ No newline at end of file diff --git a/RNS/Cryptography/aes/aes.py b/RNS/Cryptography/aes/aes.py deleted file mode 100644 index 5244b20..0000000 --- a/RNS/Cryptography/aes/aes.py +++ /dev/null @@ -1,272 +0,0 @@ -# MIT License - -# Copyright (c) 2021 Or Gur Arie - -# Permission is hereby granted, free of charge, to any person obtaining a copy -# of this software and associated documentation files (the "Software"), to deal -# in the Software without restriction, including without limitation the rights -# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell -# copies of the Software, and to permit persons to whom the Software is -# furnished to do so, subject to the following conditions: - -# The above copyright notice and this permission notice shall be included in all -# copies or substantial portions of the Software. - -# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR -# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, -# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE -# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER -# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, -# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE -# SOFTWARE. - -from .utils import * - -# TODO: Add AES-256 support to pure-python implementation - -class AES: - # AES-128 block size - block_size = 16 - # AES-128 encrypts messages with 10 rounds - _rounds = 10 - - - # initiate the AES objecy - def __init__(self, key): - """ - Initializes the object with a given key. - """ - # make sure key length is right - assert len(key) == AES.block_size - - # ExpandKey - self._round_keys = self._expand_key(key) - - - # will perform the AES ExpandKey phase - def _expand_key(self, master_key): - """ - Expands and returns a list of key matrices for the given master_key. - """ - - # Initialize round keys with raw key material. - key_columns = bytes2matrix(master_key) - iteration_size = len(master_key) // 4 - - # Each iteration has exactly as many columns as the key material. - i = 1 - while len(key_columns) < (self._rounds + 1) * 4: - # Copy previous word. - word = list(key_columns[-1]) - - # Perform schedule_core once every "row". - if len(key_columns) % iteration_size == 0: - # Circular shift. - word.append(word.pop(0)) - # Map to S-BOX. - word = [s_box[b] for b in word] - # XOR with first byte of R-CON, since the others bytes of R-CON are 0. - word[0] ^= r_con[i] - i += 1 - elif len(master_key) == 32 and len(key_columns) % iteration_size == 4: - # Run word through S-box in the fourth iteration when using a - # 256-bit key. - word = [s_box[b] for b in word] - - # XOR with equivalent word from previous iteration. - word = bytes(i^j for i, j in zip(word, key_columns[-iteration_size])) - key_columns.append(word) - - # Group key words in 4x4 byte matrices. - return [key_columns[4*i : 4*(i+1)] for i in range(len(key_columns) // 4)] - - - # encrypt a single block of data with AES - def _encrypt_block(self, plaintext): - """ - Encrypts a single block of 16 byte long plaintext. - """ - # length of a single block - assert len(plaintext) == AES.block_size - - # perform on a matrix - state = bytes2matrix(plaintext) - - # AddRoundKey - add_round_key(state, self._round_keys[0]) - - # 9 main rounds - for i in range(1, self._rounds): - # SubBytes - sub_bytes(state) - # ShiftRows - shift_rows(state) - # MixCols - mix_columns(state) - # AddRoundKey - add_round_key(state, self._round_keys[i]) - - # last round, w/t AddRoundKey step - sub_bytes(state) - shift_rows(state) - add_round_key(state, self._round_keys[-1]) - - # return the encrypted matrix as bytes - return matrix2bytes(state) - - - # decrypt a single block of data with AES - def _decrypt_block(self, ciphertext): - """ - Decrypts a single block of 16 byte long ciphertext. - """ - # length of a single block - assert len(ciphertext) == AES.block_size - - # perform on a matrix - state = bytes2matrix(ciphertext) - - # in reverse order, last round is first - add_round_key(state, self._round_keys[-1]) - inv_shift_rows(state) - inv_sub_bytes(state) - - for i in range(self._rounds - 1, 0, -1): - # nain rounds - add_round_key(state, self._round_keys[i]) - inv_mix_columns(state) - inv_shift_rows(state) - inv_sub_bytes(state) - - # initial AddRoundKey phase - add_round_key(state, self._round_keys[0]) - - # return bytes - return matrix2bytes(state) - - - # will encrypt the entire data - def encrypt(self, plaintext, iv): - """ - Encrypts `plaintext` using CBC mode and PKCS#7 padding, with the given - initialization vector (iv). - """ - # iv length must be same as block size - assert len(iv) == AES.block_size - - assert len(plaintext) % AES.block_size == 0 - - ciphertext_blocks = [] - - previous = iv - for plaintext_block in split_blocks(plaintext): - # in CBC mode every block is XOR'd with the previous block - xorred = xor_bytes(plaintext_block, previous) - - # encrypt current block - block = self._encrypt_block(xorred) - previous = block - - # append to ciphertext - ciphertext_blocks.append(block) - - # return as bytes - return b''.join(ciphertext_blocks) - - - # will decrypt the entire data - def decrypt(self, ciphertext, iv): - """ - Decrypts `ciphertext` using CBC mode and PKCS#7 padding, with the given - initialization vector (iv). - """ - # iv length must be same as block size - assert len(iv) == AES.block_size - - plaintext_blocks = [] - - previous = iv - for ciphertext_block in split_blocks(ciphertext): - # in CBC mode every block is XOR'd with the previous block - xorred = xor_bytes(previous, self._decrypt_block(ciphertext_block)) - - # append plaintext - plaintext_blocks.append(xorred) - previous = ciphertext_block - - return b''.join(plaintext_blocks) - - -def test(): - # modules and classes requiered for test only - import os - class bcolors: - OK = '\033[92m' #GREEN - WARNING = '\033[93m' #YELLOW - FAIL = '\033[91m' #RED - RESET = '\033[0m' #RESET COLOR - - # will test AES class by performing an encryption / decryption - print("AES Tests") - print("=========") - - # generate a secret key and print details - key = os.urandom(AES.block_size) - _aes = AES(key) - print(f"Algorithm: AES-CBC-{AES.block_size*8}") - print(f"Secret Key: {key.hex()}") - print() - - # test single block encryption / decryption - iv = os.urandom(AES.block_size) - - single_block_text = b"SingleBlock Text" - print("Single Block Tests") - print("------------------") - print(f"iv: {iv.hex()}") - - print(f"plain text: '{single_block_text.decode()}'") - ciphertext_block = _aes._encrypt_block(single_block_text) - plaintext_block = _aes._decrypt_block(ciphertext_block) - print(f"Ciphertext Hex: {ciphertext_block.hex()}") - print(f"Plaintext: {plaintext_block.decode()}") - assert plaintext_block == single_block_text - print(bcolors.OK + "Single Block Test Passed Successfully" + bcolors.RESET) - print() - - # test a less than a block length phrase - iv = os.urandom(AES.block_size) - - short_text = b"Just Text" - print("Short Text Tests") - print("----------------") - print(f"iv: {iv.hex()}") - print(f"plain text: '{short_text.decode()}'") - ciphertext_short = _aes.encrypt(short_text, iv) - plaintext_short = _aes.decrypt(ciphertext_short, iv) - print(f"Ciphertext Hex: {ciphertext_short.hex()}") - print(f"Plaintext: {plaintext_short.decode()}") - assert short_text == plaintext_short - print(bcolors.OK + "Short Text Test Passed Successfully" + bcolors.RESET) - print() - - # test an arbitrary length phrase - iv = os.urandom(AES.block_size) - - text = b"This Text is longer than one block" - print("Arbitrary Length Tests") - print("----------------------") - print(f"iv: {iv.hex()}") - print(f"plain text: '{text.decode()}'") - ciphertext = _aes.encrypt(text, iv) - plaintext = _aes.decrypt(ciphertext, iv) - print(f"Ciphertext Hex: {ciphertext.hex()}") - print(f"Plaintext: {plaintext.decode()}") - assert text == plaintext - print(bcolors.OK + "Arbitrary Length Text Test Passed Successfully" + bcolors.RESET) - print() - - -if __name__ == "__main__": - # test AES class - test() diff --git a/RNS/Cryptography/aes/utils.py b/RNS/Cryptography/aes/aes128.py similarity index 56% rename from RNS/Cryptography/aes/utils.py rename to RNS/Cryptography/aes/aes128.py index bc0d2dd..409e847 100644 --- a/RNS/Cryptography/aes/utils.py +++ b/RNS/Cryptography/aes/aes128.py @@ -20,10 +20,6 @@ # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE # SOFTWARE. -''' -Utils class for AES encryption / decryption -''' - ## AES lookup tables # resource: https://en.wikipedia.org/wiki/Rijndael_S-box s_box = ( @@ -138,7 +134,6 @@ def inv_mix_columns(s): mix_columns(s) - ## AES Bytes def bytes2matrix(text): """ Converts a 16-byte array into a 4x4 matrix. """ @@ -156,4 +151,176 @@ def xor_bytes(a, b): def split_blocks(message, block_size=16, require_padding=True): assert len(message) % block_size == 0 or not require_padding - return [message[i:i+16] for i in range(0, len(message), block_size)] \ No newline at end of file + return [message[i:i+16] for i in range(0, len(message), block_size)] + +class AES128: + # AES-128 block size + block_size = 16 + # AES-128 encrypts messages with 10 rounds + _rounds = 10 + + + # initiate the AES objecy + def __init__(self, key): + """ + Initializes the object with a given key. + """ + # make sure key length is right + assert len(key) == AES128.block_size + + # ExpandKey + self._round_keys = self._expand_key(key) + + + # will perform the AES ExpandKey phase + def _expand_key(self, master_key): + """ + Expands and returns a list of key matrices for the given master_key. + """ + + # Initialize round keys with raw key material. + key_columns = bytes2matrix(master_key) + iteration_size = len(master_key) // 4 + + # Each iteration has exactly as many columns as the key material. + i = 1 + while len(key_columns) < (self._rounds + 1) * 4: + # Copy previous word. + word = list(key_columns[-1]) + + # Perform schedule_core once every "row". + if len(key_columns) % iteration_size == 0: + # Circular shift. + word.append(word.pop(0)) + # Map to S-BOX. + word = [s_box[b] for b in word] + # XOR with first byte of R-CON, since the others bytes of R-CON are 0. + word[0] ^= r_con[i] + i += 1 + elif len(master_key) == 32 and len(key_columns) % iteration_size == 4: + # Run word through S-box in the fourth iteration when using a + # 256-bit key. + word = [s_box[b] for b in word] + + # XOR with equivalent word from previous iteration. + word = bytes(i^j for i, j in zip(word, key_columns[-iteration_size])) + key_columns.append(word) + + # Group key words in 4x4 byte matrices. + return [key_columns[4*i : 4*(i+1)] for i in range(len(key_columns) // 4)] + + + # encrypt a single block of data with AES + def _encrypt_block(self, plaintext): + """ + Encrypts a single block of 16 byte long plaintext. + """ + # length of a single block + assert len(plaintext) == AES128.block_size + + # perform on a matrix + state = bytes2matrix(plaintext) + + # AddRoundKey + add_round_key(state, self._round_keys[0]) + + # 9 main rounds + for i in range(1, self._rounds): + # SubBytes + sub_bytes(state) + # ShiftRows + shift_rows(state) + # MixCols + mix_columns(state) + # AddRoundKey + add_round_key(state, self._round_keys[i]) + + # last round, w/t AddRoundKey step + sub_bytes(state) + shift_rows(state) + add_round_key(state, self._round_keys[-1]) + + # return the encrypted matrix as bytes + return matrix2bytes(state) + + + # decrypt a single block of data with AES + def _decrypt_block(self, ciphertext): + """ + Decrypts a single block of 16 byte long ciphertext. + """ + # length of a single block + assert len(ciphertext) == AES128.block_size + + # perform on a matrix + state = bytes2matrix(ciphertext) + + # in reverse order, last round is first + add_round_key(state, self._round_keys[-1]) + inv_shift_rows(state) + inv_sub_bytes(state) + + for i in range(self._rounds - 1, 0, -1): + # nain rounds + add_round_key(state, self._round_keys[i]) + inv_mix_columns(state) + inv_shift_rows(state) + inv_sub_bytes(state) + + # initial AddRoundKey phase + add_round_key(state, self._round_keys[0]) + + # return bytes + return matrix2bytes(state) + + + # will encrypt the entire data + def encrypt(self, plaintext, iv): + """ + Encrypts `plaintext` using CBC mode and PKCS#7 padding, with the given + initialization vector (iv). + """ + # iv length must be same as block size + assert len(iv) == AES128.block_size + + assert len(plaintext) % AES128.block_size == 0 + + ciphertext_blocks = [] + + previous = iv + for plaintext_block in split_blocks(plaintext): + # in CBC mode every block is XOR'd with the previous block + xorred = xor_bytes(plaintext_block, previous) + + # encrypt current block + block = self._encrypt_block(xorred) + previous = block + + # append to ciphertext + ciphertext_blocks.append(block) + + # return as bytes + return b''.join(ciphertext_blocks) + + + # will decrypt the entire data + def decrypt(self, ciphertext, iv): + """ + Decrypts `ciphertext` using CBC mode and PKCS#7 padding, with the given + initialization vector (iv). + """ + # iv length must be same as block size + assert len(iv) == AES128.block_size + + plaintext_blocks = [] + + previous = iv + for ciphertext_block in split_blocks(ciphertext): + # in CBC mode every block is XOR'd with the previous block + xorred = xor_bytes(previous, self._decrypt_block(ciphertext_block)) + + # append plaintext + plaintext_blocks.append(xorred) + previous = ciphertext_block + + return b''.join(plaintext_blocks) diff --git a/RNS/Cryptography/aes/aes256.py b/RNS/Cryptography/aes/aes256.py new file mode 100644 index 0000000..aaa4be9 --- /dev/null +++ b/RNS/Cryptography/aes/aes256.py @@ -0,0 +1,447 @@ +# MIT License + +# Copyright (c) 2024 BoppreH + +# Permission is hereby granted, free of charge, to any person obtaining a copy +# of this software and associated documentation files (the "Software"), to deal +# in the Software without restriction, including without limitation the rights +# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +# copies of the Software, and to permit persons to whom the Software is +# furnished to do so, subject to the following conditions: + +# The above copyright notice and this permission notice shall be included in all +# copies or substantial portions of the Software. + +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +# SOFTWARE. + +s_box = ( + 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, +) + +inv_s_box = ( + 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, +) + + +def sub_bytes(s): + for i in range(4): + for j in range(4): + s[i][j] = s_box[s[i][j]] + + +def inv_sub_bytes(s): + for i in range(4): + for j in range(4): + s[i][j] = inv_s_box[s[i][j]] + + +def shift_rows(s): + s[0][1], s[1][1], s[2][1], s[3][1] = s[1][1], s[2][1], s[3][1], s[0][1] + s[0][2], s[1][2], s[2][2], s[3][2] = s[2][2], s[3][2], s[0][2], s[1][2] + s[0][3], s[1][3], s[2][3], s[3][3] = s[3][3], s[0][3], s[1][3], s[2][3] + + +def inv_shift_rows(s): + s[0][1], s[1][1], s[2][1], s[3][1] = s[3][1], s[0][1], s[1][1], s[2][1] + s[0][2], s[1][2], s[2][2], s[3][2] = s[2][2], s[3][2], s[0][2], s[1][2] + s[0][3], s[1][3], s[2][3], s[3][3] = s[1][3], s[2][3], s[3][3], s[0][3] + +def add_round_key(s, k): + for i in range(4): + for j in range(4): + s[i][j] ^= k[i][j] + + +# learned from https://web.archive.org/web/20100626212235/http://cs.ucsb.edu/~koc/cs178/projects/JT/aes.c +xtime = lambda a: (((a << 1) ^ 0x1B) & 0xFF) if (a & 0x80) else (a << 1) + + +def mix_single_column(a): + # see Sec 4.1.2 in The Design of Rijndael + t = a[0] ^ a[1] ^ a[2] ^ a[3] + u = a[0] + a[0] ^= t ^ xtime(a[0] ^ a[1]) + a[1] ^= t ^ xtime(a[1] ^ a[2]) + a[2] ^= t ^ xtime(a[2] ^ a[3]) + a[3] ^= t ^ xtime(a[3] ^ u) + + +def mix_columns(s): + for i in range(4): + mix_single_column(s[i]) + + +def inv_mix_columns(s): + # see Sec 4.1.3 in The Design of Rijndael + for i in range(4): + u = xtime(xtime(s[i][0] ^ s[i][2])) + v = xtime(xtime(s[i][1] ^ s[i][3])) + s[i][0] ^= u + s[i][1] ^= v + s[i][2] ^= u + s[i][3] ^= v + + mix_columns(s) + + +r_con = ( + 0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, + 0x80, 0x1B, 0x36, 0x6C, 0xD8, 0xAB, 0x4D, 0x9A, + 0x2F, 0x5E, 0xBC, 0x63, 0xC6, 0x97, 0x35, 0x6A, + 0xD4, 0xB3, 0x7D, 0xFA, 0xEF, 0xC5, 0x91, 0x39, +) + + +def bytes2matrix(text): + """ Converts a 16-byte array into a 4x4 matrix. """ + return [list(text[i:i+4]) for i in range(0, len(text), 4)] + +def matrix2bytes(matrix): + """ Converts a 4x4 matrix into a 16-byte array. """ + return bytes(sum(matrix, [])) + +def xor_bytes(a, b): + """ Returns a new byte array with the elements xor'ed. """ + return bytes(i^j for i, j in zip(a, b)) + +def inc_bytes(a): + """ Returns a new byte array with the value increment by 1 """ + out = list(a) + for i in reversed(range(len(out))): + if out[i] == 0xFF: + out[i] = 0 + else: + out[i] += 1 + break + return bytes(out) + +def pad(plaintext): + """ + Pads the given plaintext with PKCS#7 padding to a multiple of 16 bytes. + Note that if the plaintext size is a multiple of 16, + a whole block will be added. + """ + padding_len = 16 - (len(plaintext) % 16) + padding = bytes([padding_len] * padding_len) + return plaintext + padding + +def unpad(plaintext): + """ + Removes a PKCS#7 padding, returning the unpadded text and ensuring the + padding was correct. + """ + padding_len = plaintext[-1] + assert padding_len > 0 + message, padding = plaintext[:-padding_len], plaintext[-padding_len:] + assert all(p == padding_len for p in padding) + return message + +def split_blocks(message, block_size=16, require_padding=True): + assert len(message) % block_size == 0 or not require_padding + return [message[i:i+16] for i in range(0, len(message), block_size)] + + +class AES256: + """ + Class for AES-128 encryption with CBC mode and PKCS#7. + + This is a raw implementation of AES, without key stretching or IV + management. Unless you need that, please use `encrypt` and `decrypt`. + """ + rounds_by_key_size = {32: 14} + def __init__(self, master_key): + """ + Initializes the object with a given key. + """ + assert len(master_key) in AES256.rounds_by_key_size + self.n_rounds = AES256.rounds_by_key_size[len(master_key)] + self._key_matrices = self._expand_key(master_key) + + def _expand_key(self, master_key): + """ + Expands and returns a list of key matrices for the given master_key. + """ + # Initialize round keys with raw key material. + key_columns = bytes2matrix(master_key) + iteration_size = len(master_key) // 4 + + i = 1 + while len(key_columns) < (self.n_rounds + 1) * 4: + # Copy previous word. + word = list(key_columns[-1]) + + # Perform schedule_core once every "row". + if len(key_columns) % iteration_size == 0: + # Circular shift. + word.append(word.pop(0)) + # Map to S-BOX. + word = [s_box[b] for b in word] + # XOR with first byte of R-CON, since the others bytes of R-CON are 0. + word[0] ^= r_con[i] + i += 1 + elif len(master_key) == 32 and len(key_columns) % iteration_size == 4: + # Run word through S-box in the fourth iteration when using a + # 256-bit key. + word = [s_box[b] for b in word] + + # XOR with equivalent word from previous iteration. + word = xor_bytes(word, key_columns[-iteration_size]) + key_columns.append(word) + + # Group key words in 4x4 byte matrices. + return [key_columns[4*i : 4*(i+1)] for i in range(len(key_columns) // 4)] + + def encrypt_block(self, plaintext): + """ + Encrypts a single block of 16 byte long plaintext. + """ + assert len(plaintext) == 16 + + plain_state = bytes2matrix(plaintext) + + add_round_key(plain_state, self._key_matrices[0]) + + for i in range(1, self.n_rounds): + sub_bytes(plain_state) + shift_rows(plain_state) + mix_columns(plain_state) + add_round_key(plain_state, self._key_matrices[i]) + + sub_bytes(plain_state) + shift_rows(plain_state) + add_round_key(plain_state, self._key_matrices[-1]) + + return matrix2bytes(plain_state) + + def decrypt_block(self, ciphertext): + """ + Decrypts a single block of 16 byte long ciphertext. + """ + assert len(ciphertext) == 16 + + cipher_state = bytes2matrix(ciphertext) + + add_round_key(cipher_state, self._key_matrices[-1]) + inv_shift_rows(cipher_state) + inv_sub_bytes(cipher_state) + + for i in range(self.n_rounds - 1, 0, -1): + add_round_key(cipher_state, self._key_matrices[i]) + inv_mix_columns(cipher_state) + inv_shift_rows(cipher_state) + inv_sub_bytes(cipher_state) + + add_round_key(cipher_state, self._key_matrices[0]) + + return matrix2bytes(cipher_state) + + def encrypt_cbc(self, plaintext, iv): + """ + Encrypts `plaintext` using CBC mode and PKCS#7 padding, with the given + initialization vector (iv). + """ + assert len(iv) == 16 + + plaintext = pad(plaintext) + + blocks = [] + previous = iv + for plaintext_block in split_blocks(plaintext): + # CBC mode encrypt: encrypt(plaintext_block XOR previous) + block = self.encrypt_block(xor_bytes(plaintext_block, previous)) + blocks.append(block) + previous = block + + return b''.join(blocks) + + def decrypt_cbc(self, ciphertext, iv): + """ + Decrypts `ciphertext` using CBC mode and PKCS#7 padding, with the given + initialization vector (iv). + """ + assert len(iv) == 16 + + blocks = [] + previous = iv + for ciphertext_block in split_blocks(ciphertext): + # CBC mode decrypt: previous XOR decrypt(ciphertext) + blocks.append(xor_bytes(previous, self.decrypt_block(ciphertext_block))) + previous = ciphertext_block + + return unpad(b''.join(blocks)) + + def encrypt_pcbc(self, plaintext, iv): + """ + Encrypts `plaintext` using PCBC mode and PKCS#7 padding, with the given + initialization vector (iv). + """ + assert len(iv) == 16 + + plaintext = pad(plaintext) + + blocks = [] + prev_ciphertext = iv + prev_plaintext = bytes(16) + for plaintext_block in split_blocks(plaintext): + # PCBC mode encrypt: encrypt(plaintext_block XOR (prev_ciphertext XOR prev_plaintext)) + ciphertext_block = self.encrypt_block(xor_bytes(plaintext_block, xor_bytes(prev_ciphertext, prev_plaintext))) + blocks.append(ciphertext_block) + prev_ciphertext = ciphertext_block + prev_plaintext = plaintext_block + + return b''.join(blocks) + + def decrypt_pcbc(self, ciphertext, iv): + """ + Decrypts `ciphertext` using PCBC mode and PKCS#7 padding, with the given + initialization vector (iv). + """ + assert len(iv) == 16 + + blocks = [] + prev_ciphertext = iv + prev_plaintext = bytes(16) + for ciphertext_block in split_blocks(ciphertext): + # PCBC mode decrypt: (prev_plaintext XOR prev_ciphertext) XOR decrypt(ciphertext_block) + plaintext_block = xor_bytes(xor_bytes(prev_ciphertext, prev_plaintext), self.decrypt_block(ciphertext_block)) + blocks.append(plaintext_block) + prev_ciphertext = ciphertext_block + prev_plaintext = plaintext_block + + return unpad(b''.join(blocks)) + + def encrypt_cfb(self, plaintext, iv): + """ + Encrypts `plaintext` with the given initialization vector (iv). + """ + assert len(iv) == 16 + + blocks = [] + prev_ciphertext = iv + for plaintext_block in split_blocks(plaintext, require_padding=False): + # CFB mode encrypt: plaintext_block XOR encrypt(prev_ciphertext) + ciphertext_block = xor_bytes(plaintext_block, self.encrypt_block(prev_ciphertext)) + blocks.append(ciphertext_block) + prev_ciphertext = ciphertext_block + + return b''.join(blocks) + + def decrypt_cfb(self, ciphertext, iv): + """ + Decrypts `ciphertext` with the given initialization vector (iv). + """ + assert len(iv) == 16 + + blocks = [] + prev_ciphertext = iv + for ciphertext_block in split_blocks(ciphertext, require_padding=False): + # CFB mode decrypt: ciphertext XOR decrypt(prev_ciphertext) + plaintext_block = xor_bytes(ciphertext_block, self.encrypt_block(prev_ciphertext)) + blocks.append(plaintext_block) + prev_ciphertext = ciphertext_block + + return b''.join(blocks) + + def encrypt_ofb(self, plaintext, iv): + """ + Encrypts `plaintext` using OFB mode initialization vector (iv). + """ + assert len(iv) == 16 + + blocks = [] + previous = iv + for plaintext_block in split_blocks(plaintext, require_padding=False): + # OFB mode encrypt: plaintext_block XOR encrypt(previous) + block = self.encrypt_block(previous) + ciphertext_block = xor_bytes(plaintext_block, block) + blocks.append(ciphertext_block) + previous = block + + return b''.join(blocks) + + def decrypt_ofb(self, ciphertext, iv): + """ + Decrypts `ciphertext` using OFB mode initialization vector (iv). + """ + assert len(iv) == 16 + + blocks = [] + previous = iv + for ciphertext_block in split_blocks(ciphertext, require_padding=False): + # OFB mode decrypt: ciphertext XOR encrypt(previous) + block = self.encrypt_block(previous) + plaintext_block = xor_bytes(ciphertext_block, block) + blocks.append(plaintext_block) + previous = block + + return b''.join(blocks) + + def encrypt_ctr(self, plaintext, iv): + """ + Encrypts `plaintext` using CTR mode with the given nounce/IV. + """ + assert len(iv) == 16 + + blocks = [] + nonce = iv + for plaintext_block in split_blocks(plaintext, require_padding=False): + # CTR mode encrypt: plaintext_block XOR encrypt(nonce) + block = xor_bytes(plaintext_block, self.encrypt_block(nonce)) + blocks.append(block) + nonce = inc_bytes(nonce) + + return b''.join(blocks) + + def decrypt_ctr(self, ciphertext, iv): + """ + Decrypts `ciphertext` using CTR mode with the given nounce/IV. + """ + assert len(iv) == 16 + + blocks = [] + nonce = iv + for ciphertext_block in split_blocks(ciphertext, require_padding=False): + # CTR mode decrypt: ciphertext XOR encrypt(nonce) + block = xor_bytes(ciphertext_block, self.encrypt_block(nonce)) + blocks.append(block) + nonce = inc_bytes(nonce) + + return b''.join(blocks) + +__all__ = ["AES256"] \ No newline at end of file