Module refinery.units.crypto.cipher.serpent

Expand source code Browse git 
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from __future__ import annotations
from typing import List, Optional

from refinery.units.crypto.cipher import (
    Arg,
    StandardBlockCipherUnit,
)
from refinery.lib.serpent import (
    make_subkeys,
    serpent_encrypt,
    serpent_decrypt,
)
from refinery.lib.crypto import (
    BlockCipher,
    BlockCipherFactory,
    BufferType,
    CipherMode,
    CipherInterface,
)


class Serpent(BlockCipher):

    _key_data: List[int]
    _key_derivation: List[int]

    block_size = 0x10
    key_size = frozenset(range(4, 0x101, 4))

    def __init__(self, key: BufferType, mode: Optional[CipherMode], swap: bool = True):
        super().__init__(key, mode)
        self.swap = swap

    def block_decrypt(self, block) -> BufferType:
        return serpent_decrypt(block, self.key, self.swap)

    def block_encrypt(self, block) -> BufferType:
        return serpent_encrypt(block, self.key, self.swap)

    @property
    def key(self):
        try:
            return self._key_derivation
        except AttributeError:
            kd = make_subkeys(self._key_data)
            self._key_derivation = kd
            return kd

    @key.setter
    def key(self, key):
        self._key_data = key


class serpent(StandardBlockCipherUnit, cipher=BlockCipherFactory(Serpent)):
    """
    Serpent encryption and decryption. Some Serpent implementations read the bytes of each block
    in one direction, some in the other. When decryption results with this unit do not yield the
    expected result, try using the `--swap` (or `-s`) option to swap the bytes in each block.
    Furthermore, it is sometimes necessary to swap the bytes of the input key, which can be done
    by prefixing the input key by the multibin handler `snip[::-1]`.
    """
    def __init__(
        self, key, iv=b'', padding=None, mode=None, raw=False,
        swap: Arg.Switch('-s', help='Read the bytes in each block in reverse order.') = False
    ):
        super().__init__(key, iv, padding=padding, mode=mode, raw=raw, swap=swap)

    def _new_cipher(self, **optionals) -> CipherInterface:
        instance: Serpent = super()._new_cipher()
        instance.swap = self.args.swap
        return instance

Classes

class Serpent (key, mode, swap=True)

Abstract base class for refinery's block cipher interface.

Expand source code Browse git 
class Serpent(BlockCipher):

    _key_data: List[int]
    _key_derivation: List[int]

    block_size = 0x10
    key_size = frozenset(range(4, 0x101, 4))

    def __init__(self, key: BufferType, mode: Optional[CipherMode], swap: bool = True):
        super().__init__(key, mode)
        self.swap = swap

    def block_decrypt(self, block) -> BufferType:
        return serpent_decrypt(block, self.key, self.swap)

    def block_encrypt(self, block) -> BufferType:
        return serpent_encrypt(block, self.key, self.swap)

    @property
    def key(self):
        try:
            return self._key_derivation
        except AttributeError:
            kd = make_subkeys(self._key_data)
            self._key_derivation = kd
            return kd

    @key.setter
    def key(self, key):
        self._key_data = key

Ancestors

Instance variables

var key
Expand source code Browse git 
@property
def key(self):
    try:
        return self._key_derivation
    except AttributeError:
        kd = make_subkeys(self._key_data)
        self._key_derivation = kd
        return kd

Inherited members

class serpent (key, iv=b'', padding=None, mode=None, raw=False, swap=False)

Serpent encryption and decryption. Some Serpent implementations read the bytes of each block in one direction, some in the other. When decryption results with this unit do not yield the expected result, try using the --swap (or -s) option to swap the bytes in each block. Furthermore, it is sometimes necessary to swap the bytes of the input key, which can be done by prefixing the input key by the multibin handler snip[::-1].

Expand source code Browse git 
class serpent(StandardBlockCipherUnit, cipher=BlockCipherFactory(Serpent)):
    """
    Serpent encryption and decryption. Some Serpent implementations read the bytes of each block
    in one direction, some in the other. When decryption results with this unit do not yield the
    expected result, try using the `--swap` (or `-s`) option to swap the bytes in each block.
    Furthermore, it is sometimes necessary to swap the bytes of the input key, which can be done
    by prefixing the input key by the multibin handler `snip[::-1]`.
    """
    def __init__(
        self, key, iv=b'', padding=None, mode=None, raw=False,
        swap: Arg.Switch('-s', help='Read the bytes in each block in reverse order.') = False
    ):
        super().__init__(key, iv, padding=padding, mode=mode, raw=raw, swap=swap)

    def _new_cipher(self, **optionals) -> CipherInterface:
        instance: Serpent = super()._new_cipher()
        instance.swap = self.args.swap
        return instance

Ancestors

Class variables

var block_size
var key_size

Inherited members