Algorytmy kryptograficzne | Laboratorium 7

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from typing import List, Sequence
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
import os


# S-BOX (Table 4)
SBOX: List[int] = [
    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
]

# Inverse S-BOX (Table 6)
INV_SBOX: List[int] = [
    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 print_state(state: Sequence[Sequence[int]]) -> None:
    print("State:")
    for row in state:
        print(" ".join(f"{x:02x}" for x in row))


# Figure 1
def _bytes_to_state(block: bytes) -> List[List[int]]:
    return [[b for b in block[c::4]] for c in range(4)]


state = _bytes_to_state(bytes.fromhex("00112233445566778899aabbccddeeff"))
print_state(state)


# Figure 1
def _state_to_bytes(state: Sequence[Sequence[int]]) -> bytes:
    return [state[r][c] for c in range(4) for r in range(4)]


B = _state_to_bytes(
    _bytes_to_state(bytes.fromhex("00112233445566778899aabbccddeeff"))
)
print("".join(f"{x:02x}" for x in B))


# Formula (5.9)
def _add_round_key(state: List[List[int]], round_key: bytes) -> None:
    key = _bytes_to_state(round_key)
    state[:] = [
        [s ^ k for s, k in zip(s_row, k_row)]
        for s_row, k_row in zip(state, key)
    ]


# S-BOX
def _sub_bytes(state: List[List[int]], use_table: bool = True) -> None:
    if use_table:
        state[:] = [[SBOX[cell] for cell in row] for row in state]
    else:
        state[:] = [[_sbox(cell) for cell in row] for row in state]


# Inverse S-BOX
def _inv_sub_bytes(state: List[List[int]]) -> None:
    pass


def rot_word(word: List[int]):
    word[:] = word[1:4] + [word[0]]


# Formula (5.5)
def _shift_rows(state: List[List[int]]) -> None:
    rot_word(state[1])
    rot_word(state[2])
    rot_word(state[2])
    rot_word(state[3])
    rot_word(state[3])
    rot_word(state[3])


# Formula (5.12)
def _inv_shift_rows(state: List[List[int]]) -> None:
    state[1][:] = state[1][-1:] + state[1][:-1]
    state[2][:] = state[2][-2:] + state[2][:-2]
    state[3][:] = state[3][-3:] + state[3][:-3]


# Multiplication by x mod x^8+x^4+x^3+x+1 (Formula (4.5))
def _xtime(x: int) -> int:
    return (x << 1) ^ (0x11B if x & 0x80 else 0)

# Multiplicative inverse of x mod y
def _inverse(x: int, y: int) -> int:
    def deg(p: int) -> int:
        if p == 0:
            return -1
        return p.bit_length() - 1

    def mul(a: int, b: int) -> int:
        res = 0
        while b:
            if b & 1:
                res ^= a
            a <<= 1
            b >>= 1
        return res

    def divmod(a: int, b: int) -> tuple[int, int]:
        if a == 0:
            return 0, 0
        deg_a = deg(a)
        deg_b = deg(b)
        if deg_a < deg_b:
            return 0, a
        q = 0
        while deg_a >= deg_b:
            shift = deg_a - deg_b
            q ^= (1 << shift)
            a ^= (b << shift)
            deg_a = deg(a)
        return q, a

    def div(a: int, b: int) -> int:
        q, _ = divmod(a, b)
        return q

    def mod(a: int, b: int) -> int:
        _, r = divmod(a, b)
        return r

    r0, r1 = x, y
    s0, s1 = 1, 0
    while r1 != 0:
        q = div(r0, r1)
        r0, r1 = r1, mod(r0, r1)
        s0, s1 = s1, s0 ^ mul(q, s1)
    if r0 != 1:
        raise ValueError("No inverse")
    return mod(s0, y)

# Formula (5.2) and (5.4)
def _sbox(x: int) -> int:
    pass


# Formula (5.7)
def _mix_columns(state: List[List[int]]) -> None:
    for c in range(4):
        s0, s1, s2, s3 = state[0][c], state[1][c], state[2][c], state[3][c]
        state[0][c] = _xtime(s0) ^ (_xtime(s1) ^ s1) ^ s2 ^ s3
        state[1][c] = s0 ^ _xtime(s1) ^ (_xtime(s2) ^ s2) ^ s3
        state[2][c] = s0 ^ s1 ^ _xtime(s2) ^ (_xtime(s3) ^ s3)
        state[3][c] = (_xtime(s0) ^ s0) ^ s1 ^ s2 ^ _xtime(s3)


# Formula (5.14)
def _inv_mix_columns(state: List[List[int]]) -> None:
    pass


# Rcon (Table 5)
RCON: List[int] = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36]


# Formula (5.10)
def _rot_word(word: List[int]) -> List[int]:
    return word[1:] + word[:1]


# Formula (5.11)
def _sub_word(word: List[int], use_table: bool = True) -> List[int]:
    if use_table:
        return [SBOX[b] for b in word]
    else:
        return [_sbox(b) for b in word]


# Algorithm 2
def key_expand_128(key: bytes, use_table: bool = True) -> List[bytes]:
    w = [list(key[i*4:(i+1)*4]) for i in range(4)]
    for i in range(4, 44):
        temp = w[i-1][:]
        if i % 4 == 0:
            temp = _rot_word(temp)
            temp = _sub_word(temp, use_table)
            temp[0] ^= RCON[i // 4]
        w.append([a ^ b for a, b in zip(w[i-4], temp)])
    round_keys = []
    for i in range(11):
        rk = []
        for j in range(4):
            rk.extend(w[i*4 + j])
        round_keys.append(bytes(rk))
    return round_keys


# Algorithm 1
def aes128_encrypt_block(pt: bytes, key: bytes, use_table: bool = True) -> bytes:
    state = _bytes_to_state(pt)
    # print_state(state)
    round_keys = key_expand_128(key, use_table)
    # print(round_keys)
    _add_round_key(state, round_keys[0])
    # print_state(state)
    for round_num in range(1, 10):
        _sub_bytes(state, use_table)
        # print_state(state)
        _shift_rows(state)
        _mix_columns(state)
        _add_round_key(state, round_keys[round_num])
    _sub_bytes(state, use_table)
    _shift_rows(state)
    _add_round_key(state, round_keys[10])
    return bytes(state[r][c] for c in range(4) for r in range(4))


# Algorithm 3
def aes128_decrypt_block(ct: bytes, key: bytes) -> bytes:
    pass


def test() -> None:
    key = bytes.fromhex("000102030405060708090a0b0c0d0e0f")
    pt = bytes.fromhex("00112233445566778899aabbccddeeff")
    expected = bytes.fromhex("69c4e0d86a7b0430d8cdb78070b4c55a")

    ct = aes128_encrypt_block(pt, key)
    assert ct == expected
    print("OK (with table)")

    ct = aes128_encrypt_block(pt, key, use_table=False)
    assert ct == expected
    print("OK (without table)")

    for _ in range(10):
        key = os.urandom(16)
        pt = os.urandom(16)
        ct = aes128_encrypt_block(pt, key)
        cipher = Cipher(algorithms.AES(key), modes.ECB())
        encryptor = cipher.encryptor()
        ct_crypto = encryptor.update(pt) + encryptor.finalize()
        assert ct == ct_crypto, f"error: {ct.hex()} != {ct_crypto.hex()}"
        print("passed random")

    rt = aes128_decrypt_block(ct, key)
    assert rt == pt

    print("decrypt OK")

    rt = aes128_decrypt_block(ct, key)
    assert rt == pt

    print("OK")


if __name__ == "__main__":
    test()