Module refinery.units.crypto.keyderive.deskd

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from refinery.units import RefineryPartialResult
from refinery.units.crypto.keyderive import Arg, KeyDerivation


_DES_PARITYTABLE = bytearray((
    0x01, 0x01, 0x02, 0x02, 0x04, 0x04, 0x07, 0x07,
    0x08, 0x08, 0x0B, 0x0B, 0x0D, 0x0D, 0x0E, 0x0E,
    0x10, 0x10, 0x13, 0x13, 0x15, 0x15, 0x16, 0x16,
    0x19, 0x19, 0x1A, 0x1A, 0x1C, 0x1C, 0x1F, 0x1F,
    0x20, 0x20, 0x23, 0x23, 0x25, 0x25, 0x26, 0x26,
    0x29, 0x29, 0x2A, 0x2A, 0x2C, 0x2C, 0x2F, 0x2F,
    0x31, 0x31, 0x32, 0x32, 0x34, 0x34, 0x37, 0x37,
    0x38, 0x38, 0x3B, 0x3B, 0x3D, 0x3D, 0x3E, 0x3E,
    0x40, 0x40, 0x43, 0x43, 0x45, 0x45, 0x46, 0x46,
    0x49, 0x49, 0x4A, 0x4A, 0x4C, 0x4C, 0x4F, 0x4F,
    0x51, 0x51, 0x52, 0x52, 0x54, 0x54, 0x57, 0x57,
    0x58, 0x58, 0x5B, 0x5B, 0x5D, 0x5D, 0x5E, 0x5E,
    0x61, 0x61, 0x62, 0x62, 0x64, 0x64, 0x67, 0x67,
    0x68, 0x68, 0x6B, 0x6B, 0x6D, 0x6D, 0x6E, 0x6E,
    0x70, 0x70, 0x73, 0x73, 0x75, 0x75, 0x76, 0x76,
    0x79, 0x79, 0x7A, 0x7A, 0x7C, 0x7C, 0x7F, 0x7F,
    0x80, 0x80, 0x83, 0x83, 0x85, 0x85, 0x86, 0x86,
    0x89, 0x89, 0x8A, 0x8A, 0x8C, 0x8C, 0x8F, 0x8F,
    0x91, 0x91, 0x92, 0x92, 0x94, 0x94, 0x97, 0x97,
    0x98, 0x98, 0x9B, 0x9B, 0x9D, 0x9D, 0x9E, 0x9E,
    0xA1, 0xA1, 0xA2, 0xA2, 0xA4, 0xA4, 0xA7, 0xA7,
    0xA8, 0xA8, 0xAB, 0xAB, 0xAD, 0xAD, 0xAE, 0xAE,
    0xB0, 0xB0, 0xB3, 0xB3, 0xB5, 0xB5, 0xB6, 0xB6,
    0xB9, 0xB9, 0xBA, 0xBA, 0xBC, 0xBC, 0xBF, 0xBF,
    0xC1, 0xC1, 0xC2, 0xC2, 0xC4, 0xC4, 0xC7, 0xC7,
    0xC8, 0xC8, 0xCB, 0xCB, 0xCD, 0xCD, 0xCE, 0xCE,
    0xD0, 0xD0, 0xD3, 0xD3, 0xD5, 0xD5, 0xD6, 0xD6,
    0xD9, 0xD9, 0xDA, 0xDA, 0xDC, 0xDC, 0xDF, 0xDF,
    0xE0, 0xE0, 0xE3, 0xE3, 0xE5, 0xE5, 0xE6, 0xE6,
    0xE9, 0xE9, 0xEA, 0xEA, 0xEC, 0xEC, 0xEF, 0xEF,
    0xF1, 0xF1, 0xF2, 0xF2, 0xF4, 0xF4, 0xF7, 0xF7,
    0xF8, 0xF8, 0xFB, 0xFB, 0xFD, 0xFD, 0xFE, 0xFE
))


def des_set_odd_parity(key: bytearray):
    key[:] = (_DES_PARITYTABLE[b] for b in key)


class deskd(KeyDerivation):
    """
    Stands for "DES Key Derivation". It implements the same functionality as `DES_string_to_key` in OpenSSL. It
    converts a string to an 8 byte DES key with odd byte parity, per FIPS specification. This is not a modern
    key derivation function.
    """
    def __init__(self, size: Arg(help='The number of bytes to generate, default is the maximum of 8.') = 8):
        super().__init__(size=size, salt=None)

    def process(self, password):
        from Cryptodome.Cipher import DES
        from Cryptodome.Util.strxor import strxor

        key = bytearray(8)

        for i, j in enumerate(password):
            if ((i % 16) < 8):
                key[i % 8] ^= (j << 1) & 0xFF
            else:
                j = (((j << 4) & 0xf0) | ((j >> 4) & 0x0f))
                j = (((j << 2) & 0xcc) | ((j >> 2) & 0x33))
                j = (((j << 1) & 0xaa) | ((j >> 1) & 0x55))
                key[7 - (i % 8)] ^= j

        des_set_odd_parity(key)

        if password:
            n = len(password)
            password = password.ljust(n + 7 - ((n - 1) % 8), b'\0')
            des = DES.new(key, DES.MODE_ECB)
            for k in range(0, n, 8):
                key[:] = des.encrypt(strxor(password[k:k + 8], key))
            des_set_odd_parity(key)

        if self.args.size > 8:
            raise RefineryPartialResult('can provide at most 8 bytes.', partial=key)

        return key[:self.args.size]