Source code for cryptography.hazmat.primitives.hashes

# 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

import abc

import six

from cryptography import utils
from cryptography.exceptions import (
    AlreadyFinalized,
    UnsupportedAlgorithm,
    _Reasons,
)
from cryptography.hazmat.backends import _get_backend
from cryptography.hazmat.backends.interfaces import HashBackend


[docs]@six.add_metaclass(abc.ABCMeta) class HashAlgorithm(object): @abc.abstractproperty def name(self): """ A string naming this algorithm (e.g. "sha256", "md5"). """ @abc.abstractproperty def digest_size(self): """ The size of the resulting digest in bytes. """
[docs]@six.add_metaclass(abc.ABCMeta) class HashContext(object): @abc.abstractproperty def algorithm(self): """ A HashAlgorithm that will be used by this context. """
[docs] @abc.abstractmethod def update(self, data): """ Processes the provided bytes through the hash. """
[docs] @abc.abstractmethod def finalize(self): """ Finalizes the hash context and returns the hash digest as bytes. """
[docs] @abc.abstractmethod def copy(self): """ Return a HashContext that is a copy of the current context. """
@six.add_metaclass(abc.ABCMeta) class ExtendableOutputFunction(object): """ An interface for extendable output functions. """
[docs]@utils.register_interface(HashContext) class Hash(object): def __init__(self, algorithm, backend=None, ctx=None): backend = _get_backend(backend) if not isinstance(backend, HashBackend): raise UnsupportedAlgorithm( "Backend object does not implement HashBackend.", _Reasons.BACKEND_MISSING_INTERFACE, ) if not isinstance(algorithm, HashAlgorithm): raise TypeError("Expected instance of hashes.HashAlgorithm.") self._algorithm = algorithm self._backend = backend if ctx is None: self._ctx = self._backend.create_hash_ctx(self.algorithm) else: self._ctx = ctx algorithm = utils.read_only_property("_algorithm")
[docs] def update(self, data): if self._ctx is None: raise AlreadyFinalized("Context was already finalized.") utils._check_byteslike("data", data) self._ctx.update(data)
[docs] def copy(self): if self._ctx is None: raise AlreadyFinalized("Context was already finalized.") return Hash( self.algorithm, backend=self._backend, ctx=self._ctx.copy() )
[docs] def finalize(self): if self._ctx is None: raise AlreadyFinalized("Context was already finalized.") digest = self._ctx.finalize() self._ctx = None return digest
[docs]@utils.register_interface(HashAlgorithm) class SHA1(object): name = "sha1" digest_size = 20 block_size = 64
[docs]@utils.register_interface(HashAlgorithm) class SHA512_224(object): # noqa: N801 name = "sha512-224" digest_size = 28 block_size = 128
[docs]@utils.register_interface(HashAlgorithm) class SHA512_256(object): # noqa: N801 name = "sha512-256" digest_size = 32 block_size = 128
[docs]@utils.register_interface(HashAlgorithm) class SHA224(object): name = "sha224" digest_size = 28 block_size = 64
[docs]@utils.register_interface(HashAlgorithm) class SHA256(object): name = "sha256" digest_size = 32 block_size = 64
[docs]@utils.register_interface(HashAlgorithm) class SHA384(object): name = "sha384" digest_size = 48 block_size = 128
[docs]@utils.register_interface(HashAlgorithm) class SHA512(object): name = "sha512" digest_size = 64 block_size = 128
[docs]@utils.register_interface(HashAlgorithm) class SHA3_224(object): # noqa: N801 name = "sha3-224" digest_size = 28
[docs]@utils.register_interface(HashAlgorithm) class SHA3_256(object): # noqa: N801 name = "sha3-256" digest_size = 32
[docs]@utils.register_interface(HashAlgorithm) class SHA3_384(object): # noqa: N801 name = "sha3-384" digest_size = 48
[docs]@utils.register_interface(HashAlgorithm) class SHA3_512(object): # noqa: N801 name = "sha3-512" digest_size = 64
[docs]@utils.register_interface(HashAlgorithm) @utils.register_interface(ExtendableOutputFunction) class SHAKE128(object): name = "shake128" def __init__(self, digest_size): if not isinstance(digest_size, six.integer_types): raise TypeError("digest_size must be an integer") if digest_size < 1: raise ValueError("digest_size must be a positive integer") self._digest_size = digest_size digest_size = utils.read_only_property("_digest_size")
[docs]@utils.register_interface(HashAlgorithm) @utils.register_interface(ExtendableOutputFunction) class SHAKE256(object): name = "shake256" def __init__(self, digest_size): if not isinstance(digest_size, six.integer_types): raise TypeError("digest_size must be an integer") if digest_size < 1: raise ValueError("digest_size must be a positive integer") self._digest_size = digest_size digest_size = utils.read_only_property("_digest_size")
[docs]@utils.register_interface(HashAlgorithm) class MD5(object): name = "md5" digest_size = 16 block_size = 64
[docs]@utils.register_interface(HashAlgorithm) class BLAKE2b(object): name = "blake2b" _max_digest_size = 64 _min_digest_size = 1 block_size = 128 def __init__(self, digest_size): if digest_size != 64: raise ValueError("Digest size must be 64") self._digest_size = digest_size digest_size = utils.read_only_property("_digest_size")
[docs]@utils.register_interface(HashAlgorithm) class BLAKE2s(object): name = "blake2s" block_size = 64 _max_digest_size = 32 _min_digest_size = 1 def __init__(self, digest_size): if digest_size != 32: raise ValueError("Digest size must be 32") self._digest_size = digest_size digest_size = utils.read_only_property("_digest_size")