DeDRM_tools/DeDRM_calibre_plugin/DeDRM_plugin/python_des.py

#!/usr/bin/env python
# vim:ts=4:sw=4:softtabstop=4:smarttab:expandtab
import sys

ECB =   0
CBC =   1
class Des(object):
    __pc1 = [56, 48, 40, 32, 24, 16,  8,  0, 57, 49, 41, 33, 25, 17,
          9,  1, 58, 50, 42, 34, 26, 18, 10,  2, 59, 51, 43, 35,
         62, 54, 46, 38, 30, 22, 14,  6, 61, 53, 45, 37, 29, 21,
         13,  5, 60, 52, 44, 36, 28, 20, 12,  4, 27, 19, 11,  3]
    __left_rotations = [1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1]
    __pc2 = [13, 16, 10, 23,  0,  4,2, 27, 14,  5, 20,  9,
        22, 18, 11,  3, 25,  7, 15,  6, 26, 19, 12,  1,
        40, 51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47,
        43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31]
    __ip = [57, 49, 41, 33, 25, 17, 9,  1,      59, 51, 43, 35, 27, 19, 11, 3,
        61, 53, 45, 37, 29, 21, 13, 5,  63, 55, 47, 39, 31, 23, 15, 7,
        56, 48, 40, 32, 24, 16, 8,  0,  58, 50, 42, 34, 26, 18, 10, 2,
        60, 52, 44, 36, 28, 20, 12, 4,  62, 54, 46, 38, 30, 22, 14, 6]
    __expansion_table = [31,  0,  1,  2,  3,  4, 3,  4,  5,  6,  7,  8,
         7,  8,  9, 10, 11, 12,11, 12, 13, 14, 15, 16,
        15, 16, 17, 18, 19, 20,19, 20, 21, 22, 23, 24,
        23, 24, 25, 26, 27, 28,27, 28, 29, 30, 31,  0]
    __sbox = [[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
         0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
         4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
         15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13],
        [15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
         3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
         0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
         13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9],
        [10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
         13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
         13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
         1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12],
        [7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
         13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
         10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
         3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14],
        [2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
         14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
         4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
         11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3],
        [12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
         10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
         9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
         4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13],
        [4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
         13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
         1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
         6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12],
        [13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
         1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
         7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
         2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11],]
    __p = [15, 6, 19, 20, 28, 11,27, 16, 0, 14, 22, 25,
        4, 17, 30, 9, 1, 7,23,13, 31, 26, 2, 8,18, 12, 29, 5, 21, 10,3, 24]
    __fp = [39,  7, 47, 15, 55, 23, 63, 31,38,  6, 46, 14, 54, 22, 62, 30,
        37,  5, 45, 13, 53, 21, 61, 29,36,  4, 44, 12, 52, 20, 60, 28,
        35,  3, 43, 11, 51, 19, 59, 27,34,  2, 42, 10, 50, 18, 58, 26,
        33,  1, 41,  9, 49, 17, 57, 25,32,  0, 40,  8, 48, 16, 56, 24]
    # Type of crypting being done
    ENCRYPT =   0x00
    DECRYPT =   0x01
    def __init__(self, key, mode=ECB, IV=None):
        if len(key) != 8:
            raise ValueError("Invalid DES key size. Key must be exactly 8 bytes long.")
        self.block_size = 8
        self.key_size = 8
        self.__padding = ''
        self.setMode(mode)
        if IV:
            self.setIV(IV)
        self.L = []
        self.R = []
        self.Kn = [ [0] * 48 ] * 16     # 16 48-bit keys (K1 - K16)
        self.final = []
        self.setKey(key)
    def getKey(self):
        return self.__key
    def setKey(self, key):
        self.__key = key
        self.__create_sub_keys()
    def getMode(self):
        return self.__mode
    def setMode(self, mode):
        self.__mode = mode
    def getIV(self):
        return self.__iv
    def setIV(self, IV):
        if not IV or len(IV) != self.block_size:
            raise ValueError("Invalid Initial Value (IV), must be a multiple of " + str(self.block_size) + " bytes")
        self.__iv = IV
    def getPadding(self):
        return self.__padding
    def __String_to_BitList(self, data):
        l = len(data) * 8
        result = [0] * l
        pos = 0
        for c in data:
            i = 7
            ch = ord(c)
            while i >= 0:
                if ch & (1 << i) != 0:
                    result[pos] = 1
                else:
                    result[pos] = 0
                pos += 1
                i -= 1
        return result
    def __BitList_to_String(self, data):
        result = ''
        pos = 0
        c = 0
        while pos < len(data):
            c += data[pos] << (7 - (pos % 8))
            if (pos % 8) == 7:
                result += chr(c)
                c = 0
            pos += 1
        return result
    def __permutate(self, table, block):
        return [block[x] for x in table]
    def __create_sub_keys(self):
        key = self.__permutate(Des.__pc1, self.__String_to_BitList(self.getKey()))
        i = 0
        self.L = key[:28]
        self.R = key[28:]
        while i < 16:
            j = 0
            while j < Des.__left_rotations[i]:
                self.L.append(self.L[0])
                del self.L[0]
                self.R.append(self.R[0])
                del self.R[0]
                j += 1
            self.Kn[i] = self.__permutate(Des.__pc2, self.L + self.R)
            i += 1
    def __des_crypt(self, block, crypt_type):
        block = self.__permutate(Des.__ip, block)
        self.L = block[:32]
        self.R = block[32:]
        if crypt_type == Des.ENCRYPT:
            iteration = 0
            iteration_adjustment = 1
        else:
            iteration = 15
            iteration_adjustment = -1
        i = 0
        while i < 16:
            tempR = self.R[:]
            self.R = self.__permutate(Des.__expansion_table, self.R)
            self.R = [x ^ y for x,y in zip(self.R, self.Kn[iteration])]
            B = [self.R[:6], self.R[6:12], self.R[12:18], self.R[18:24], self.R[24:30], self.R[30:36], self.R[36:42], self.R[42:]]
            j = 0
            Bn = [0] * 32
            pos = 0
            while j < 8:
                m = (B[j][0] << 1) + B[j][5]
                n = (B[j][1] << 3) + (B[j][2] << 2) + (B[j][3] << 1) + B[j][4]
                v = Des.__sbox[j][(m << 4) + n]
                Bn[pos] = (v & 8) >> 3
                Bn[pos + 1] = (v & 4) >> 2
                Bn[pos + 2] = (v & 2) >> 1
                Bn[pos + 3] = v & 1
                pos += 4
                j += 1
            self.R = self.__permutate(Des.__p, Bn)
            self.R = [x ^ y for x, y in zip(self.R, self.L)]
            self.L = tempR
            i += 1
            iteration += iteration_adjustment
        self.final = self.__permutate(Des.__fp, self.R + self.L)
        return self.final
    def crypt(self, data, crypt_type):
        if not data:
            return ''
        if len(data) % self.block_size != 0:
            if crypt_type == Des.DECRYPT: # Decryption must work on 8 byte blocks
                raise ValueError("Invalid data length, data must be a multiple of " + str(self.block_size) + " bytes\n.")
            if not self.getPadding():
                raise ValueError("Invalid data length, data must be a multiple of " + str(self.block_size) + " bytes\n. Try setting the optional padding character")
            else:
                data += (self.block_size - (len(data) % self.block_size)) * self.getPadding()
        if self.getMode() == CBC:
            if self.getIV():
                iv = self.__String_to_BitList(self.getIV())
            else:
                raise ValueError("For CBC mode, you must supply the Initial Value (IV) for ciphering")
        i = 0
        dict = {}
        result = []
        while i < len(data):
            block = self.__String_to_BitList(data[i:i+8])
            if self.getMode() == CBC:
                if crypt_type == Des.ENCRYPT:
                    block = [x ^ y for x, y in zip(block, iv)]
                processed_block = self.__des_crypt(block, crypt_type)
                if crypt_type == Des.DECRYPT:
                    processed_block = [x ^ y for x, y in zip(processed_block, iv)]
                    iv = block
                else:
                    iv = processed_block
            else:
                processed_block = self.__des_crypt(block, crypt_type)
            result.append(self.__BitList_to_String(processed_block))
            i += 8
        if crypt_type == Des.DECRYPT and self.getPadding():
            s = result[-1]
            while s[-1] == self.getPadding():
                s = s[:-1]
            result[-1] = s
        return ''.join(result)
    def encrypt(self, data, pad=''):
        self.__padding = pad
        return self.crypt(data, Des.ENCRYPT)
    def decrypt(self, data, pad=''):
        self.__padding = pad
        return self.crypt(data, Des.DECRYPT)