185 lines
4.6 KiB
Python
185 lines
4.6 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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from __future__ import absolute_import, division, print_function
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import abc
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import six
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from cryptography import utils
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from cryptography.exceptions import (
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AlreadyFinalized, UnsupportedAlgorithm, _Reasons
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)
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from cryptography.hazmat.backends.interfaces import HashBackend
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@six.add_metaclass(abc.ABCMeta)
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class HashAlgorithm(object):
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@abc.abstractproperty
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def name(self):
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"""
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A string naming this algorithm (e.g. "sha256", "md5").
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"""
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@abc.abstractproperty
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def digest_size(self):
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"""
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The size of the resulting digest in bytes.
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"""
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@six.add_metaclass(abc.ABCMeta)
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class HashContext(object):
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@abc.abstractproperty
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def algorithm(self):
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"""
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A HashAlgorithm that will be used by this context.
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"""
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@abc.abstractmethod
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def update(self, data):
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"""
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Processes the provided bytes through the hash.
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"""
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@abc.abstractmethod
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def finalize(self):
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"""
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Finalizes the hash context and returns the hash digest as bytes.
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"""
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@abc.abstractmethod
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def copy(self):
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"""
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Return a HashContext that is a copy of the current context.
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"""
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@utils.register_interface(HashContext)
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class Hash(object):
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def __init__(self, algorithm, backend, ctx=None):
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if not isinstance(backend, HashBackend):
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raise UnsupportedAlgorithm(
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"Backend object does not implement HashBackend.",
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_Reasons.BACKEND_MISSING_INTERFACE
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)
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if not isinstance(algorithm, HashAlgorithm):
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raise TypeError("Expected instance of hashes.HashAlgorithm.")
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self._algorithm = algorithm
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self._backend = backend
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if ctx is None:
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self._ctx = self._backend.create_hash_ctx(self.algorithm)
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else:
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self._ctx = ctx
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algorithm = utils.read_only_property("_algorithm")
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def update(self, data):
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if self._ctx is None:
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raise AlreadyFinalized("Context was already finalized.")
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if not isinstance(data, bytes):
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raise TypeError("data must be bytes.")
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self._ctx.update(data)
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def copy(self):
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if self._ctx is None:
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raise AlreadyFinalized("Context was already finalized.")
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return Hash(
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self.algorithm, backend=self._backend, ctx=self._ctx.copy()
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)
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def finalize(self):
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if self._ctx is None:
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raise AlreadyFinalized("Context was already finalized.")
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digest = self._ctx.finalize()
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self._ctx = None
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return digest
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@utils.register_interface(HashAlgorithm)
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class SHA1(object):
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name = "sha1"
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digest_size = 20
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block_size = 64
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@utils.register_interface(HashAlgorithm)
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class SHA224(object):
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name = "sha224"
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digest_size = 28
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block_size = 64
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@utils.register_interface(HashAlgorithm)
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class SHA256(object):
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name = "sha256"
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digest_size = 32
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block_size = 64
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@utils.register_interface(HashAlgorithm)
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class SHA384(object):
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name = "sha384"
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digest_size = 48
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block_size = 128
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@utils.register_interface(HashAlgorithm)
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class SHA512(object):
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name = "sha512"
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digest_size = 64
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block_size = 128
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@utils.register_interface(HashAlgorithm)
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class MD5(object):
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name = "md5"
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digest_size = 16
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block_size = 64
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@utils.register_interface(HashAlgorithm)
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class BLAKE2b(object):
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name = "blake2b"
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_max_digest_size = 64
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_min_digest_size = 1
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block_size = 128
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def __init__(self, digest_size):
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if (
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digest_size > self._max_digest_size or
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digest_size < self._min_digest_size
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):
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raise ValueError("Digest size must be {0}-{1}".format(
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self._min_digest_size, self._max_digest_size)
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)
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self._digest_size = digest_size
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digest_size = utils.read_only_property("_digest_size")
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@utils.register_interface(HashAlgorithm)
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class BLAKE2s(object):
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name = "blake2s"
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block_size = 64
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_max_digest_size = 32
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_min_digest_size = 1
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def __init__(self, digest_size):
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if (
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digest_size > self._max_digest_size or
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digest_size < self._min_digest_size
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):
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raise ValueError("Digest size must be {0}-{1}".format(
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self._min_digest_size, self._max_digest_size)
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)
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self._digest_size = digest_size
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digest_size = utils.read_only_property("_digest_size")
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