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Commit fb77b72b authored by Vincent Namy (EDU_GE)'s avatar Vincent Namy (EDU_GE)
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Add aes support

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Protocole/aes.py 0 → 100755
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#!/usr/bin/env python3
"""
MIT license
Origin : https://github.com/boppreh/aes/tree/master
Simplified for education by vincent.namy@edu.ge.ch
"""
"""
This is an exercise in secure symmetric-key encryption, implemented in pure
Python (no external libraries needed).
Original AES-128 implementation by Bo Zhu (http://about.bozhu.me) at
https://github.com/bozhu/AES-Python . PKCS#7 padding, CBC mode, PKBDF2, HMAC,
byte array and string support added by me at https://github.com/boppreh/aes.
Other block modes contributed by @righthandabacus.
Although this is an exercise, the `encrypt` and `decrypt` functions should
provide reasonable security to encrypted messages.
"""
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,
)
def sub_bytes(s):
for i in range(4):
for j in range(4):
s[i][j] = 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 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])
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 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 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 AES:
"""
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 = {16: 10, 24: 12, 32: 14}
def __init__(self, master_key):
"""
Initializes the object with a given key.
"""
assert len(master_key) in AES.rounds_by_key_size
self.n_rounds = AES.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 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)
__all__ = ["AES"]
if __name__ == '__main__':
#import aes
import random
key = bytes([ random.getrandbits(8) for _ in range(16)])
iv = bytes([ 0 for _ in range(16)])
cipher = AES(key)
message = b'Attack at dawn'
encrypted = cipher.encrypt_cfb(message, iv)
decrypted = cipher.decrypt_cfb(encrypted, iv)
print(encrypted, decrypted)
\ No newline at end of file
Protocole/aes_full.py 0 → 100755
+ 512
− 0
View file @ fb77b72b
#!/usr/bin/env python3
"""
MIT license
Origin : https://github.com/boppreh/aes/tree/master
Simplified for education by vincent.namy@edu.ge.ch
"""
"""
This is an exercise in secure symmetric-key encryption, implemented in pure
Python (no external libraries needed).
Original AES-128 implementation by Bo Zhu (http://about.bozhu.me) at
https://github.com/bozhu/AES-Python . PKCS#7 padding, CBC mode, PKBDF2, HMAC,
byte array and string support added by me at https://github.com/boppreh/aes.
Other block modes contributed by @righthandabacus.
Although this is an exercise, the `encrypt` and `decrypt` functions should
provide reasonable security to encrypted messages.
"""
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 AES:
"""
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 = {16: 10, 24: 12, 32: 14}
def __init__(self, master_key):
"""
Initializes the object with a given key.
"""
assert len(master_key) in AES.rounds_by_key_size
self.n_rounds = AES.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__ = ["AES"]
if __name__ == '__main__':
import random
from microbit import running_time
key = bytes([ random.getrandbits(8) for _ in range(16)])
iv = bytes([ 0 for _ in range(16)])
cipher = AES(key)
nSamples = 10
# print("CBC : ") # Pas secure https://fr.wikipedia.org/wiki/Mode_d'op%C3%A9ration_(cryptographie)#%C2%AB_Cipher_Block_Chaining_%C2%BB_(CBC):_encha%C3%AEnement_de_blocs
# t=[]
# for i in range(nSamples):
# t0 = running_time()
# encrypted = cipher.encrypt_cbc(b'Attack at dawn', iv)
# decrypted = cipher.decrypt_cbc(encrypted, iv)
# t. append(running_time()-t0)
#
# print(encrypted, decrypted,t)
#
#
# print("PCBC : ") # https://fr.wikipedia.org/wiki/Mode_d'op%C3%A9ration_(cryptographie)#%C2%AB_Propagating_Cipher_Block_Chaining_%C2%BB_(PCBC):_chiffrement_par_propagation_des_chiffr%C3%A9s_en_chaine
# t=[]
# for i in range(nSamples):
# t0 = running_time()
# encrypted = cipher.encrypt_pcbc(b'Attack at dawn', iv)
# decrypted = cipher.decrypt_pcbc(encrypted, iv)
# t. append(running_time()-t0)
#
# print(encrypted, decrypted,t)
#
#
# print("CFB : ") # Symétrique : https://fr.wikipedia.org/wiki/Mode_d'op%C3%A9ration_(cryptographie)#%C2%AB_Cipher_Feedback_Block_%C2%BB_(CFB)_:_chiffrement_%C3%A0_r%C3%A9troaction
# t=[]
# for i in range(nSamples):
# t0 = running_time()
# encrypted = cipher.encrypt_cfb(b'Attack at dawn', iv)
# decrypted = cipher.decrypt_cfb(encrypted, iv)
# t. append(running_time()-t0)
#
# print(encrypted, decrypted,t)
#
#
# print("OFB : ")# Pas secure https://fr.wikipedia.org/wiki/Mode_d'op%C3%A9ration_(cryptographie)#%C2%AB_Output_Feedback_%C2%BB_(OFB):_chiffrement_%C3%A0_r%C3%A9troaction_de_sortie
# t=[]
# for i in range(nSamples):
# t0 = running_time()
# encrypted = cipher.encrypt_ofb(b'Attack at dawn', iv)
# decrypted = cipher.decrypt_ofb(encrypted, iv)
# t. append(running_time()-t0)
#
# print(encrypted, decrypted,t)
#
print("CTR : ") # https://fr.wikipedia.org/wiki/Mode_d'op%C3%A9ration_(cryptographie)#%C2%AB_CounTeR_%C2%BB_(CTR):_chiffrement_bas%C3%A9_sur_compteur
t=[]
for i in range(nSamples):
t0 = running_time()
encrypted = cipher.encrypt_ctr(b'Attack at dawn', iv)
decrypted = cipher.decrypt_ctr(encrypted, iv)
t. append(running_time()-t0)
print(encrypted, decrypted,t)
\ No newline at end of file
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