codekingpro/portable-devtools

1# This file is dual licensed under the terms of the Apache License, Version2# 2.0, and the BSD License. See the LICENSE file in the root of this repository3# for complete details.4 5from __future__ import annotations6 7import abc8 9from cryptography import utils10from cryptography.hazmat.bindings._rust import (11    ANSIX923PaddingContext,12    ANSIX923UnpaddingContext,13    PKCS7PaddingContext,14    PKCS7UnpaddingContext,15)16 17 18class PaddingContext(metaclass=abc.ABCMeta):19    @abc.abstractmethod20    def update(self, data: utils.Buffer) -> bytes:21        """22        Pads the provided bytes and returns any available data as bytes.23        """24 25    @abc.abstractmethod26    def finalize(self) -> bytes:27        """28        Finalize the padding, returns bytes.29        """30 31 32def _byte_padding_check(block_size: int) -> None:33    if not (0 <= block_size <= 2040):34        raise ValueError("block_size must be in range(0, 2041).")35 36    if block_size % 8 != 0:37        raise ValueError("block_size must be a multiple of 8.")38 39 40class PKCS7:41    def __init__(self, block_size: int):42        _byte_padding_check(block_size)43        self.block_size = block_size44 45    def padder(self) -> PaddingContext:46        return PKCS7PaddingContext(self.block_size)47 48    def unpadder(self) -> PaddingContext:49        return PKCS7UnpaddingContext(self.block_size)50 51 52PaddingContext.register(PKCS7PaddingContext)53PaddingContext.register(PKCS7UnpaddingContext)54 55 56class ANSIX923:57    def __init__(self, block_size: int):58        _byte_padding_check(block_size)59        self.block_size = block_size60 61    def padder(self) -> PaddingContext:62        return ANSIX923PaddingContext(self.block_size)63 64    def unpadder(self) -> PaddingContext:65        return ANSIX923UnpaddingContext(self.block_size)66 67 68PaddingContext.register(ANSIX923PaddingContext)69PaddingContext.register(ANSIX923UnpaddingContext)70