text: from cryptowork.core.utils import bitlist_to_string, string_to_bitlist
  
  
  class des():
      """DES encryption/decrytpion class
      Only Supports CBC (Cypher Block Chaining) modes with PKCS5 padding technique.
      cryptowork.algo.des.des(key, IV)
      key  -> Bytes containing the encryption key, must be exactly 8 bytes
      IV   -> Initial Value bytes, Must be 8 bytes in length.
      """
  
      # Permutation and translation tables for DES
      __pc_1 = [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
                ]
  
      # number left rotations of pc1
      __left_rotations = [
          1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
      ]
  
      # permuted choice key (table 2)
      __pc_2 = [
          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
      ]
  
      # initial permutation IP
      __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 for turning 32 bit blocks into 48 bits
      __e_box = [
          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
      ]
  
      # The (in)famous S-boxes
      __s_boxes = [
          # S1
          [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],
  
          # S2
          [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],
  
          # S3
          [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],
  
          # S4
          [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],
  
          # S5
          [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],
  
          # S6
          [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],
  
          # S7
          [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],
  
          # S8
          [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],
      ]
  
      # 32-bit permutation function P used on the output of the S-boxes
      __p_box = [
          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
      ]
  
      # final permutation IP^-1
      __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
  
      # Initialisation
      def __init__(self, key: str, IV: bytes) -> None:
          # Sanity checking of arguments.
          if len(key) != 8:
              raise ValueError(
                  "Invalid DES key size. Key must be exactly 8 bytes long.")
  
          IV = self._guard_against_unicode(IV)
          self.block_size = 8
          # Sanity checking of arguments.
          if len(IV) != self.block_size:
              raise ValueError(
                  "Invalid Initial Value (IV), must be a multiple of " + str(self.block_size) + " bytes")
  
          # Set the passed in variables
          self._iv = IV
          self.key_size = 8
  
          self.L = []
          self.R = []
          self.Kn = [[0] * 48] * 16  # 16 48-bit keys (K1 - K16)
          self.final = []
  
          self.init_key(key)
  
      def init_key(self, key):
          """Will init the crypting key for this object. Must be 8 bytes."""
          self.set_key(key)
          self.__create_sub_keys()
  
      def get_key(self) -> bytes:
          """get_key() -> bytes"""
          return self.__key
  
      def set_key(self, key):
          """Will set the crypting key for this object."""
          key = self._guard_against_unicode(key)
          self.__key = key
  
      def get_iv(self) -> bytes:
          """get_iv() -> bytes"""
          return self._iv
  
      def set_iv(self, IV):
          """Will set the Initial Value"""
          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")
          IV = self._guard_against_unicode(IV)
          self._iv = IV
  
      def _pad_data(self, data: bytes):
          pad_len = 8 - (len(data) % self.block_size)
          data += bytes([pad_len] * pad_len)
  
          return data
  
      def _unpad_data(self, data):
          # Unpad data depending on the mode.
          if not data:
              return data
          pad_len = data[-1]
          data = data[:-pad_len]
  
          return data
  
      def _guard_against_unicode(self, data):
          # Only accept byte strings or ascii unicode values, otherwise
          # there is no way to correctly decode the data into bytes.
          if isinstance(data, str):
              # Only accept ascii unicode values.
              try:
                  return data.encode('ascii')
              except UnicodeEncodeError:
                  pass
              raise ValueError(
                  "cryptowork.des can only work with encoded strings, not Unicode.")
          return data
  
      def __permutate(self, table: list, block: list) -> list:
          """Permutate this block with the specified table"""
          return list(map(lambda x: block[x], table))
  
      # Transform the secret key, so that it is ready for data processing
      # Create the 16 subkeys, K[1] - K[16]
      def __create_sub_keys(self):
          """Create the 16 subkeys K[1] to K[16] from the given key"""
          key = self.__permutate(
              des.__pc_1, string_to_bitlist(self.get_key()))
          i = 0
          # Split into Left and Right sections
          self.L = key[:28]
          self.R = key[28:]
          while i < 16:
              j = 0
              # Perform circular left shifts
              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
  
              # Create one of the 16 subkeys through pc2 permutation
              self.Kn[i] = self.__permutate(des.__pc_2, self.L + self.R)
  
              i += 1
  
      # Main part of the encryption algorithm, the number cruncher :)
      def __des_crypt(self, block, crypt_type):
          """Crypt the block of data through DES bit-manipulation"""
          block = self.__permutate(des.__ip, block)
          self.L = block[:32]
          self.R = block[32:]
  
          # Encryption starts from Kn[1] through to Kn[16]
          if crypt_type == des.ENCRYPT:
              iteration = 0
              iteration_adjustment = 1
          # Decryption starts from Kn[16] down to Kn[1]
          else:
              iteration = 15
              iteration_adjustment = -1
  
          i = 0
          while i < 16:
              # Make a copy of R[i-1], this will later become L[i]
              tempR = self.R[:]
  
              # Permutate R[i - 1] to start creating R[i]
              self.R = self.__permutate(des.__e_box, self.R)
  
              # Exclusive or R[i - 1] with K[i], create B[1] to B[8] whilst here
              self.R = list(map(lambda x, y: x ^ y, 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:]]
  
              # Permutate B[1] to B[8] using the S-Boxes
              j = 0
              Bn = [0] * 32
              pos = 0
              while j < 8:
                  # Work out the offsets
                  m = (B[j][0] << 1) + B[j][5]
                  n = (B[j][1] << 3) + (B[j][2] << 2) + (B[j][3] << 1) + B[j][4]
  
                  # Find the permutation value
                  v = des.__s_boxes[j][(m << 4) + n]
  
                  # Turn value into bits, add it to result: Bn
                  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
  
              # Permutate the concatination of B[1] to B[8] (Bn)
              self.R = self.__permutate(des.__p_box, Bn)
  
              # Xor with L[i - 1]
              self.R = list(map(lambda x, y: x ^ y, self.R, self.L))
  
              # L[i] becomes R[i - 1]
              self.L = tempR
  
              i += 1
              iteration += iteration_adjustment
  
          # Final permutation of R[16]L[16]
          self.final = self.__permutate(des.__fp, self.R + self.L)
          return self.final
  
      # Data to be encrypted/decrypted
  
      def crypt(self, data, crypt_type):
          """Crypt the data in blocks, running it through des_crypt()"""
  
          # Error check the data
          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 self.get_iv():
              iv = string_to_bitlist(self.get_iv())
          else:
              raise ValueError(
                  "You must supply the Initial Value (IV) for ciphering")
  
          # Split the data into blocks, crypting each one seperately
          i = 0
          dict = {}
          result = []
          while i < len(data):
              block = string_to_bitlist(data[i:i+8])
  
              if crypt_type == des.ENCRYPT:
                  block = list(map(lambda x, y: x ^ y, block, iv))
  
              processed_block = self.__des_crypt(block, crypt_type)
  
              if crypt_type == des.DECRYPT:
                  processed_block = list(
                      map(lambda x, y: x ^ y, processed_block, iv))
                  iv = block
              else:
                  iv = processed_block
  
              result.append(bitlist_to_string(processed_block))
              i += 8
  
          # Return the full crypted string
          return bytes.fromhex('').join(result)
  
      def encrypt(self, data):
          """encrypt(data) -> bytes
          data : Bytes to be encrypted, must be a multiple of 8 bytes
          and will be encrypted with the already specified key. 
          In PKCS5, as bytes will then added to ensure 
          the be padded data is a multiple of 8 bytes.
          """
          data = self._guard_against_unicode(data)
          data = self._pad_data(data)
          return self.crypt(data, des.ENCRYPT)
  
      def decrypt(self, data) -> bytes:
          """decrypt(data) -> bytes
          data : Bytes to be decrypted
          The data must be a multiple of 8 bytes and will be decrypted
          with the already specified key. In PKCS5, the special
          padding end markers will be removed from the data after decrypting.
          """
          data = self._guard_against_unicode(data)
          data = self.crypt(data, des.DECRYPT)
          return self._unpad_data(data)
  