text: # This file is dual licensed under the terms of the Apache License, Version
  # 2.0, and the BSD License. See the LICENSE file in the root of this repository
  # for complete details.
  
  from __future__ import absolute_import, division, print_function
  
  from cryptography import utils
  from cryptography.hazmat.primitives.ciphers import (
      BlockCipherAlgorithm, CipherAlgorithm
  )
  from cryptography.hazmat.primitives.ciphers.modes import ModeWithNonce
  
  
  def _verify_key_size(algorithm, key):
      # Verify that the key size matches the expected key size
      if len(key) * 8 not in algorithm.key_sizes:
          raise ValueError("Invalid key size ({0}) for {1}.".format(
              len(key) * 8, algorithm.name
          ))
      return key
  
  
  @utils.register_interface(BlockCipherAlgorithm)
  @utils.register_interface(CipherAlgorithm)
  class AES(object):
      name = "AES"
      block_size = 128
      # 512 added to support AES-256-XTS, which uses 512-bit keys
      key_sizes = frozenset([128, 192, 256, 512])
  
      def __init__(self, key):
          self.key = _verify_key_size(self, key)
  
      @property
      def key_size(self):
          return len(self.key) * 8
  
  
  @utils.register_interface(BlockCipherAlgorithm)
  @utils.register_interface(CipherAlgorithm)
  class Camellia(object):
      name = "camellia"
      block_size = 128
      key_sizes = frozenset([128, 192, 256])
  
      def __init__(self, key):
          self.key = _verify_key_size(self, key)
  
      @property
      def key_size(self):
          return len(self.key) * 8
  
  
  @utils.register_interface(BlockCipherAlgorithm)
  @utils.register_interface(CipherAlgorithm)
  class TripleDES(object):
      name = "3DES"
      block_size = 64
      key_sizes = frozenset([64, 128, 192])
  
      def __init__(self, key):
          if len(key) == 8:
              key += key + key
          elif len(key) == 16:
              key += key[:8]
          self.key = _verify_key_size(self, key)
  
      @property
      def key_size(self):
          return len(self.key) * 8
  
  
  @utils.register_interface(BlockCipherAlgorithm)
  @utils.register_interface(CipherAlgorithm)
  class Blowfish(object):
      name = "Blowfish"
      block_size = 64
      key_sizes = frozenset(range(32, 449, 8))
  
      def __init__(self, key):
          self.key = _verify_key_size(self, key)
  
      @property
      def key_size(self):
          return len(self.key) * 8
  
  
  @utils.register_interface(BlockCipherAlgorithm)
  @utils.register_interface(CipherAlgorithm)
  class CAST5(object):
      name = "CAST5"
      block_size = 64
      key_sizes = frozenset(range(40, 129, 8))
  
      def __init__(self, key):
          self.key = _verify_key_size(self, key)
  
      @property
      def key_size(self):
          return len(self.key) * 8
  
  
  @utils.register_interface(CipherAlgorithm)
  class ARC4(object):
      name = "RC4"
      key_sizes = frozenset([40, 56, 64, 80, 128, 160, 192, 256])
  
      def __init__(self, key):
          self.key = _verify_key_size(self, key)
  
      @property
      def key_size(self):
          return len(self.key) * 8
  
  
  @utils.register_interface(CipherAlgorithm)
  class IDEA(object):
      name = "IDEA"
      block_size = 64
      key_sizes = frozenset([128])
  
      def __init__(self, key):
          self.key = _verify_key_size(self, key)
  
      @property
      def key_size(self):
          return len(self.key) * 8
  
  
  @utils.register_interface(BlockCipherAlgorithm)
  @utils.register_interface(CipherAlgorithm)
  class SEED(object):
      name = "SEED"
      block_size = 128
      key_sizes = frozenset([128])
  
      def __init__(self, key):
          self.key = _verify_key_size(self, key)
  
      @property
      def key_size(self):
          return len(self.key) * 8
  
  
  @utils.register_interface(CipherAlgorithm)
  @utils.register_interface(ModeWithNonce)
  class ChaCha20(object):
      name = "ChaCha20"
      key_sizes = frozenset([256])
  
      def __init__(self, key, nonce):
          self.key = _verify_key_size(self, key)
          if not isinstance(nonce, bytes):
              raise TypeError("nonce must be bytes")
  
          if len(nonce) != 16:
              raise ValueError("nonce must be 128-bits (16 bytes)")
  
          self._nonce = nonce
  
      nonce = utils.read_only_property("_nonce")
  
      @property
      def key_size(self):
          return len(self.key) * 8
  