Merge pull request #1658 from reaperhulk/move-hash-interfaces

Move hash interfaces

22 files changed, 182 insertions, 154 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 79663ab6..a42a4d18 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -10,6 +10,10 @@ Changelog
   now load elliptic curve public keys.
 * Added
   :func:`~cryptography.hazmat.primitives.asymmetric.rsa.rsa_recover_prime_factors`
+* :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm` and
+  :class:`~cryptography.hazmat.primitives.hashes.HashContext` were moved from
+  :mod:`~cryptography.hazmat.primitives.interfaces` to
+  :mod:`~cryptography.hazmat.primitives.hashes`.
 * :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`,
   :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParametersWithNumbers`,
   :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`,
diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index b828fa73..15d8b980 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -91,7 +91,7 @@ A specific ``backend`` may provide one or more of these interfaces.
         Check if the specified ``algorithm`` is supported by this backend.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :returns: ``True`` if the specified ``algorithm`` is supported by this
@@ -101,15 +101,15 @@ A specific ``backend`` may provide one or more of these interfaces.
     .. method:: create_hash_ctx(algorithm)
 
         Create a
-        :class:`~cryptography.hazmat.primitives.interfaces.HashContext` that
+        :class:`~cryptography.hazmat.primitives.hashes.HashContext` that
         uses the specified ``algorithm`` to calculate a message digest.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :returns:
-            :class:`~cryptography.hazmat.primitives.interfaces.HashContext`
+            :class:`~cryptography.hazmat.primitives.hashes.HashContext`
 
 
 .. class:: HMACBackend
@@ -127,7 +127,7 @@ A specific ``backend`` may provide one or more of these interfaces.
         Check if the specified ``algorithm`` is supported by this backend.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :returns: ``True`` if the specified ``algorithm`` is supported for HMAC
@@ -136,16 +136,16 @@ A specific ``backend`` may provide one or more of these interfaces.
     .. method:: create_hmac_ctx(algorithm)
 
         Create a
-        :class:`~cryptography.hazmat.primitives.interfaces.HashContext` that
+        :class:`~cryptography.hazmat.primitives.hashes.HashContext` that
         uses the specified ``algorithm`` to calculate a hash-based message
         authentication code.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :returns:
-            :class:`~cryptography.hazmat.primitives.interfaces.HashContext`
+            :class:`~cryptography.hazmat.primitives.hashes.HashContext`
 
 
 .. class:: CMACBackend
@@ -191,7 +191,7 @@ A specific ``backend`` may provide one or more of these interfaces.
         Check if the specified ``algorithm`` is supported by this backend.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :returns: ``True`` if the specified ``algorithm`` is supported for
@@ -200,7 +200,7 @@ A specific ``backend`` may provide one or more of these interfaces.
     .. method:: derive_pbkdf2_hmac(self, algorithm, length, salt, iterations, key_material)
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :param int length: The desired length of the derived key. Maximum is
@@ -343,7 +343,7 @@ A specific ``backend`` may provide one or more of these interfaces.
     .. method:: dsa_hash_supported(algorithm)
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :returns: ``True`` if the specified ``algorithm`` is supported by this
diff --git a/docs/hazmat/primitives/asymmetric/dsa.rst b/docs/hazmat/primitives/asymmetric/dsa.rst
index 59c0d973..36bc801f 100644
--- a/docs/hazmat/primitives/asymmetric/dsa.rst
+++ b/docs/hazmat/primitives/asymmetric/dsa.rst
@@ -267,7 +267,7 @@ Key interfaces
         :rfc:`6979`.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :param backend: A
@@ -330,7 +330,7 @@ Key interfaces
             specified in :rfc:`6979`.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :param backend: A
diff --git a/docs/hazmat/primitives/asymmetric/ec.rst b/docs/hazmat/primitives/asymmetric/ec.rst
index caa3f285..5b114710 100644
--- a/docs/hazmat/primitives/asymmetric/ec.rst
+++ b/docs/hazmat/primitives/asymmetric/ec.rst
@@ -32,7 +32,7 @@ Elliptic Curve Signature Algorithms
     `FIPS 186-3`_, and later in `FIPS 186-4`_.
 
     :param algorithm: An instance of a
-        :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+        :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         provider.
 
     .. doctest::
@@ -282,7 +282,7 @@ Key Interfaces
 
     .. attribute:: algorithm
 
-        :type: :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+        :type: :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
 
         The digest algorithm to be used with the signature scheme.
 
diff --git a/docs/hazmat/primitives/asymmetric/rsa.rst b/docs/hazmat/primitives/asymmetric/rsa.rst
index e516f749..4855a45c 100644
--- a/docs/hazmat/primitives/asymmetric/rsa.rst
+++ b/docs/hazmat/primitives/asymmetric/rsa.rst
@@ -252,7 +252,7 @@ Mask generation functions
     in :class:`PSS` padding. It takes a hash algorithm and a salt length.
 
     :param algorithm: An instance of a
-        :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+        :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         provider.
 
 Numbers
@@ -429,7 +429,7 @@ Key interfaces
             provider.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :returns:
@@ -499,7 +499,7 @@ Key interfaces
             provider.
 
         :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             provider.
 
         :returns:
diff --git a/docs/hazmat/primitives/cryptographic-hashes.rst b/docs/hazmat/primitives/cryptographic-hashes.rst
index c8b56eb9..49288326 100644
--- a/docs/hazmat/primitives/cryptographic-hashes.rst
+++ b/docs/hazmat/primitives/cryptographic-hashes.rst
@@ -12,9 +12,9 @@ Message digests
     results (with a high probability) in different digests.
 
     This is an implementation of
-    :class:`~cryptography.hazmat.primitives.interfaces.HashContext` meant to
+    :class:`~cryptography.hazmat.primitives.hashes.HashContext` meant to
     be used with
-    :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+    :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
     implementations to provide an incremental interface to calculating
     various message digests.
 
@@ -39,7 +39,7 @@ Message digests
     `Lifetimes of cryptographic hash functions`_.
 
     :param algorithm: A
-        :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+        :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         provider such as those described in
         :ref:`below <cryptographic-hash-algorithms>`.
     :param backend: A
@@ -146,4 +146,48 @@ MD5
     message digest and has practical known collision attacks.
 
 
+Interfaces
+~~~~~~~~~~
+
+.. class:: HashAlgorithm
+
+    .. attribute:: name
+
+        :type: str
+
+        The standard name for the hash algorithm, for example: ``"sha256"`` or
+        ``"whirlpool"``.
+
+    .. attribute:: digest_size
+
+        :type: int
+
+        The size of the resulting digest in bytes.
+
+    .. attribute:: block_size
+
+        :type: int
+
+        The internal block size of the hash algorithm in bytes.
+
+
+.. class:: HashContext
+
+    .. attribute:: algorithm
+
+        A :class:`HashAlgorithm` that will be used by this context.
+
+    .. method:: update(data)
+
+        :param bytes data: The data you want to hash.
+
+    .. method:: finalize()
+
+        :return: The final digest as bytes.
+
+    .. method:: copy()
+
+        :return: A :class:`HashContext` that is a copy of the current context.
+
+
 .. _`Lifetimes of cryptographic hash functions`: http://valerieaurora.org/hash.html
diff --git a/docs/hazmat/primitives/interfaces.rst b/docs/hazmat/primitives/interfaces.rst
index cd21ea1a..86a3a7e4 100644
--- a/docs/hazmat/primitives/interfaces.rst
+++ b/docs/hazmat/primitives/interfaces.rst
@@ -160,52 +160,6 @@ In 0.8 the EC key interfaces were moved to the
 :mod:`cryptography.hazmat.primitives.asymmetric.ec` module.
 
 
-Hash algorithms
----------------
-
-.. class:: HashAlgorithm
-
-    .. attribute:: name
-
-        :type: str
-
-        The standard name for the hash algorithm, for example: ``"sha256"`` or
-        ``"whirlpool"``.
-
-    .. attribute:: digest_size
-
-        :type: int
-
-        The size of the resulting digest in bytes.
-
-    .. attribute:: block_size
-
-        :type: int
-
-        The internal block size of the hash algorithm in bytes.
-
-
-.. class:: HashContext
-
-    .. attribute:: algorithm
-
-        A :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm` that
-        will be used by this context.
-
-    .. method:: update(data)
-
-        :param bytes data: The data you want to hash.
-
-    .. method:: finalize()
-
-        :return: The final digest as bytes.
-
-    .. method:: copy()
-
-        :return: A :class:`~cryptography.hazmat.primitives.interfaces.HashContext`
-             that is a copy of the current context.
-
-
 Key derivation functions
 ------------------------
 
diff --git a/docs/hazmat/primitives/key-derivation-functions.rst b/docs/hazmat/primitives/key-derivation-functions.rst
index 60096870..4a47159f 100644
--- a/docs/hazmat/primitives/key-derivation-functions.rst
+++ b/docs/hazmat/primitives/key-derivation-functions.rst
@@ -69,7 +69,7 @@ Different KDFs are suitable for different tasks such as:
         >>> kdf.verify(b"my great password", key)
 
     :param algorithm: An instance of a
-        :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+        :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         provider.
     :param int length: The desired length of the derived key. Maximum is
         (2\ :sup:`32` - 1) * ``algorithm.digest_size``.
@@ -169,7 +169,7 @@ Different KDFs are suitable for different tasks such as:
         >>> hkdf.verify(b"input key", key)
 
     :param algorithm: An instance of a
-        :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+        :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         provider.
 
     :param int length: The desired length of the derived key. Maximum is
@@ -270,7 +270,7 @@ Different KDFs are suitable for different tasks such as:
         >>> hkdf.verify(key_material, key)
 
     :param algorithm: An instance of a
-        :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+        :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         provider.
 
     :param int length: The desired length of the derived key. Maximum is
diff --git a/docs/hazmat/primitives/mac/hmac.rst b/docs/hazmat/primitives/mac/hmac.rst
index ce566c5c..2515ac91 100644
--- a/docs/hazmat/primitives/mac/hmac.rst
+++ b/docs/hazmat/primitives/mac/hmac.rst
@@ -18,7 +18,7 @@ of a message.
 .. class:: HMAC(key, algorithm, backend)
 
     HMAC objects take a ``key`` and a
-    :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm` provider.
+    :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm` provider.
     The ``key`` should be :doc:`randomly generated bytes </random-numbers>` and
     is recommended to be equal in length to the ``digest_size`` of the hash
     function chosen. You must keep the ``key`` secret.
@@ -39,7 +39,7 @@ of a message.
     raised.
 
     If ``algorithm`` isn't a
-    :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm` provider
+    :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm` provider
     then ``TypeError`` will be raised.
 
     To check that a given signature is correct use the :meth:`verify` method.
@@ -56,7 +56,7 @@ of a message.
 
     :param bytes key: Secret key as ``bytes``.
     :param algorithm: An
-        :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+        :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         provider such as those described in
         :ref:`Cryptographic Hashes <cryptographic-hash-algorithms>`.
     :param backend: An
diff --git a/docs/x509.rst b/docs/x509.rst
index 9bd9bd59..587fd884 100644
--- a/docs/x509.rst
+++ b/docs/x509.rst
@@ -103,7 +103,7 @@ X.509 Certificate Object
     .. method:: fingerprint(algorithm)
 
         :param algorithm: The
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             that will be used to generate the fingerprint.
 
         :return bytes: The fingerprint using the supplied hash algorithm as
diff --git a/src/cryptography/hazmat/backends/commoncrypto/hashes.py b/src/cryptography/hazmat/backends/commoncrypto/hashes.py
index 8ce20f6b..a54e9833 100644
--- a/src/cryptography/hazmat/backends/commoncrypto/hashes.py
+++ b/src/cryptography/hazmat/backends/commoncrypto/hashes.py
@@ -6,10 +6,10 @@ from __future__ import absolute_import, division, print_function
 
 from cryptography import utils
 from cryptography.exceptions import UnsupportedAlgorithm, _Reasons
-from cryptography.hazmat.primitives import interfaces
+from cryptography.hazmat.primitives import hashes
 
 
-@utils.register_interface(interfaces.HashContext)
+@utils.register_interface(hashes.HashContext)
 class _HashContext(object):
     def __init__(self, backend, algorithm, ctx=None):
         self._algorithm = algorithm
diff --git a/src/cryptography/hazmat/backends/commoncrypto/hmac.py b/src/cryptography/hazmat/backends/commoncrypto/hmac.py
index 942688e6..ae623d84 100644
--- a/src/cryptography/hazmat/backends/commoncrypto/hmac.py
+++ b/src/cryptography/hazmat/backends/commoncrypto/hmac.py
@@ -8,11 +8,11 @@ from cryptography import utils
 from cryptography.exceptions import (
     InvalidSignature, UnsupportedAlgorithm, _Reasons
 )
-from cryptography.hazmat.primitives import constant_time, interfaces
+from cryptography.hazmat.primitives import constant_time, hashes, interfaces
 
 
 @utils.register_interface(interfaces.MACContext)
-@utils.register_interface(interfaces.HashContext)
+@utils.register_interface(hashes.HashContext)
 class _HMACContext(object):
     def __init__(self, backend, key, algorithm, ctx=None):
         self._algorithm = algorithm
diff --git a/src/cryptography/hazmat/backends/openssl/hashes.py b/src/cryptography/hazmat/backends/openssl/hashes.py
index 8dc3c01f..2c1702f8 100644
--- a/src/cryptography/hazmat/backends/openssl/hashes.py
+++ b/src/cryptography/hazmat/backends/openssl/hashes.py
@@ -7,10 +7,10 @@ from __future__ import absolute_import, division, print_function
 
 from cryptography import utils
 from cryptography.exceptions import UnsupportedAlgorithm, _Reasons
-from cryptography.hazmat.primitives import interfaces
+from cryptography.hazmat.primitives import hashes
 
 
-@utils.register_interface(interfaces.HashContext)
+@utils.register_interface(hashes.HashContext)
 class _HashContext(object):
     def __init__(self, backend, algorithm, ctx=None):
         self._algorithm = algorithm
diff --git a/src/cryptography/hazmat/backends/openssl/hmac.py b/src/cryptography/hazmat/backends/openssl/hmac.py
index 356d2aa8..dfe9d93b 100644
--- a/src/cryptography/hazmat/backends/openssl/hmac.py
+++ b/src/cryptography/hazmat/backends/openssl/hmac.py
@@ -9,11 +9,11 @@ from cryptography import utils
 from cryptography.exceptions import (
     InvalidSignature, UnsupportedAlgorithm, _Reasons
 )
-from cryptography.hazmat.primitives import constant_time, interfaces
+from cryptography.hazmat.primitives import constant_time, hashes, interfaces
 
 
 @utils.register_interface(interfaces.MACContext)
-@utils.register_interface(interfaces.HashContext)
+@utils.register_interface(hashes.HashContext)
 class _HMACContext(object):
     def __init__(self, backend, key, algorithm, ctx=None):
         self._algorithm = algorithm
diff --git a/src/cryptography/hazmat/primitives/asymmetric/padding.py b/src/cryptography/hazmat/primitives/asymmetric/padding.py
index f51b201d..d0c3eade 100644
--- a/src/cryptography/hazmat/primitives/asymmetric/padding.py
+++ b/src/cryptography/hazmat/primitives/asymmetric/padding.py
@@ -7,7 +7,7 @@ from __future__ import absolute_import, division, print_function
 import six
 
 from cryptography import utils
-from cryptography.hazmat.primitives import interfaces
+from cryptography.hazmat.primitives import hashes, interfaces
 
 
 @utils.register_interface(interfaces.AsymmetricPadding)
@@ -38,8 +38,8 @@ class OAEP(object):
     name = "EME-OAEP"
 
     def __init__(self, mgf, algorithm, label):
-        if not isinstance(algorithm, interfaces.HashAlgorithm):
-            raise TypeError("Expected instance of interfaces.HashAlgorithm.")
+        if not isinstance(algorithm, hashes.HashAlgorithm):
+            raise TypeError("Expected instance of hashes.HashAlgorithm.")
 
         self._mgf = mgf
         self._algorithm = algorithm
@@ -50,7 +50,7 @@ class MGF1(object):
     MAX_LENGTH = object()
 
     def __init__(self, algorithm):
-        if not isinstance(algorithm, interfaces.HashAlgorithm):
-            raise TypeError("Expected instance of interfaces.HashAlgorithm.")
+        if not isinstance(algorithm, hashes.HashAlgorithm):
+            raise TypeError("Expected instance of hashes.HashAlgorithm.")
 
         self._algorithm = algorithm
diff --git a/src/cryptography/hazmat/primitives/hashes.py b/src/cryptography/hazmat/primitives/hashes.py
index f00c0741..6bc8500b 100644
--- a/src/cryptography/hazmat/primitives/hashes.py
+++ b/src/cryptography/hazmat/primitives/hashes.py
@@ -4,15 +4,66 @@
 
 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.interfaces import HashBackend
-from cryptography.hazmat.primitives import interfaces
 
 
-@utils.register_interface(interfaces.HashContext)
+@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.
+        """
+
+    @abc.abstractproperty
+    def block_size(self):
+        """
+        The internal block size of the hash algorithm in bytes.
+        """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class HashContext(object):
+    @abc.abstractproperty
+    def algorithm(self):
+        """
+        A HashAlgorithm that will be used by this context.
+        """
+
+    @abc.abstractmethod
+    def update(self, data):
+        """
+        Processes the provided bytes through the hash.
+        """
+
+    @abc.abstractmethod
+    def finalize(self):
+        """
+        Finalizes the hash context and returns the hash digest as bytes.
+        """
+
+    @abc.abstractmethod
+    def copy(self):
+        """
+        Return a HashContext that is a copy of the current context.
+        """
+
+
+@utils.register_interface(HashContext)
 class Hash(object):
     def __init__(self, algorithm, backend, ctx=None):
         if not isinstance(backend, HashBackend):
@@ -21,8 +72,8 @@ class Hash(object):
                 _Reasons.BACKEND_MISSING_INTERFACE
             )
 
-        if not isinstance(algorithm, interfaces.HashAlgorithm):
-            raise TypeError("Expected instance of interfaces.HashAlgorithm.")
+        if not isinstance(algorithm, HashAlgorithm):
+            raise TypeError("Expected instance of hashes.HashAlgorithm.")
         self._algorithm = algorithm
 
         self._backend = backend
@@ -56,56 +107,56 @@ class Hash(object):
         return digest
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(HashAlgorithm)
 class SHA1(object):
     name = "sha1"
     digest_size = 20
     block_size = 64
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(HashAlgorithm)
 class SHA224(object):
     name = "sha224"
     digest_size = 28
     block_size = 64
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(HashAlgorithm)
 class SHA256(object):
     name = "sha256"
     digest_size = 32
     block_size = 64
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(HashAlgorithm)
 class SHA384(object):
     name = "sha384"
     digest_size = 48
     block_size = 128
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(HashAlgorithm)
 class SHA512(object):
     name = "sha512"
     digest_size = 64
     block_size = 128
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(HashAlgorithm)
 class RIPEMD160(object):
     name = "ripemd160"
     digest_size = 20
     block_size = 64
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(HashAlgorithm)
 class Whirlpool(object):
     name = "whirlpool"
     digest_size = 64
     block_size = 64
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(HashAlgorithm)
 class MD5(object):
     name = "md5"
     digest_size = 16
diff --git a/src/cryptography/hazmat/primitives/hmac.py b/src/cryptography/hazmat/primitives/hmac.py
index 17f1084d..15b9ee6e 100644
--- a/src/cryptography/hazmat/primitives/hmac.py
+++ b/src/cryptography/hazmat/primitives/hmac.py
@@ -9,11 +9,11 @@ from cryptography.exceptions import (
     AlreadyFinalized, UnsupportedAlgorithm, _Reasons
 )
 from cryptography.hazmat.backends.interfaces import HMACBackend
-from cryptography.hazmat.primitives import interfaces
+from cryptography.hazmat.primitives import hashes, interfaces
 
 
 @utils.register_interface(interfaces.MACContext)
-@utils.register_interface(interfaces.HashContext)
+@utils.register_interface(hashes.HashContext)
 class HMAC(object):
     def __init__(self, key, algorithm, backend, ctx=None):
         if not isinstance(backend, HMACBackend):
@@ -22,8 +22,8 @@ class HMAC(object):
                 _Reasons.BACKEND_MISSING_INTERFACE
             )
 
-        if not isinstance(algorithm, interfaces.HashAlgorithm):
-            raise TypeError("Expected instance of interfaces.HashAlgorithm.")
+        if not isinstance(algorithm, hashes.HashAlgorithm):
+            raise TypeError("Expected instance of hashes.HashAlgorithm.")
         self._algorithm = algorithm
 
         self._backend = backend
diff --git a/src/cryptography/hazmat/primitives/interfaces/__init__.py b/src/cryptography/hazmat/primitives/interfaces/__init__.py
index a2154df5..17bac1e6 100644
--- a/src/cryptography/hazmat/primitives/interfaces/__init__.py
+++ b/src/cryptography/hazmat/primitives/interfaces/__init__.py
@@ -9,6 +9,7 @@ import abc
 import six
 
 from cryptography import utils
+from cryptography.hazmat.primitives import hashes
 from cryptography.hazmat.primitives.asymmetric import dsa, ec, rsa
 from cryptography.hazmat.primitives.interfaces.ciphers import (
     BlockCipherAlgorithm, CipherAlgorithm, Mode,
@@ -202,52 +203,26 @@ class PaddingContext(object):
         """
 
 
-@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.
-        """
-
-    @abc.abstractproperty
-    def block_size(self):
-        """
-        The internal block size of the hash algorithm in bytes.
-        """
-
-
-@six.add_metaclass(abc.ABCMeta)
-class HashContext(object):
-    @abc.abstractproperty
-    def algorithm(self):
-        """
-        A HashAlgorithm that will be used by this context.
-        """
-
-    @abc.abstractmethod
-    def update(self, data):
-        """
-        Processes the provided bytes through the hash.
-        """
+HashContext = utils.deprecated(
+    hashes.HashContext,
+    __name__,
+    (
+        "The HashContext interface has moved to the "
+        "cryptography.hazmat.primitives.hashes module"
+    ),
+    utils.DeprecatedIn08
+)
 
-    @abc.abstractmethod
-    def finalize(self):
-        """
-        Finalizes the hash context and returns the hash digest as bytes.
-        """
 
-    @abc.abstractmethod
-    def copy(self):
-        """
-        Return a HashContext that is a copy of the current context.
-        """
+HashAlgorithm = utils.deprecated(
+    hashes.HashAlgorithm,
+    __name__,
+    (
+        "The HashAlgorithm interface has moved to the "
+        "cryptography.hazmat.primitives.hashes module"
+    ),
+    utils.DeprecatedIn08
+)
 
 
 RSAPrivateKey = utils.deprecated(
diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py
index 5b5c7bd7..97d58085 100644
--- a/tests/hazmat/backends/test_openssl.py
+++ b/tests/hazmat/backends/test_openssl.py
@@ -49,7 +49,7 @@ class DummyPadding(object):
     name = "dummy-cipher"
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(hashes.HashAlgorithm)
 class DummyHash(object):
     name = "dummy-hash"
     block_size = None
diff --git a/tests/hazmat/primitives/test_hashes.py b/tests/hazmat/primitives/test_hashes.py
index d4bf6229..d6fd727d 100644
--- a/tests/hazmat/primitives/test_hashes.py
+++ b/tests/hazmat/primitives/test_hashes.py
@@ -13,14 +13,14 @@ import six
 from cryptography import utils
 from cryptography.exceptions import AlreadyFinalized, _Reasons
 from cryptography.hazmat.backends.interfaces import HashBackend
-from cryptography.hazmat.primitives import hashes, interfaces
+from cryptography.hazmat.primitives import hashes
 
 from .utils import generate_base_hash_test
 from ..backends.test_multibackend import DummyHashBackend
 from ...utils import raises_unsupported_algorithm
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(hashes.HashAlgorithm)
 class UnsupportedDummyHash(object):
     name = "unsupported-dummy-hash"
     block_size = None
diff --git a/tests/hazmat/primitives/test_hmac.py b/tests/hazmat/primitives/test_hmac.py
index e31ddc8e..acd03323 100644
--- a/tests/hazmat/primitives/test_hmac.py
+++ b/tests/hazmat/primitives/test_hmac.py
@@ -15,14 +15,14 @@ from cryptography.exceptions import (
     AlreadyFinalized, InvalidSignature, _Reasons
 )
 from cryptography.hazmat.backends.interfaces import HMACBackend
-from cryptography.hazmat.primitives import hashes, hmac, interfaces
+from cryptography.hazmat.primitives import hashes, hmac
 
 from .utils import generate_base_hmac_test
 from ..backends.test_multibackend import DummyHMACBackend
 from ...utils import raises_unsupported_algorithm
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(hashes.HashAlgorithm)
 class UnsupportedDummyHash(object):
     name = "unsupported-dummy-hash"
     block_size = None
diff --git a/tests/hazmat/primitives/test_pbkdf2hmac.py b/tests/hazmat/primitives/test_pbkdf2hmac.py
index caa6a852..df49d23c 100644
--- a/tests/hazmat/primitives/test_pbkdf2hmac.py
+++ b/tests/hazmat/primitives/test_pbkdf2hmac.py
@@ -13,13 +13,13 @@ from cryptography.exceptions import (
     AlreadyFinalized, InvalidKey, _Reasons
 )
 from cryptography.hazmat.backends import default_backend
-from cryptography.hazmat.primitives import hashes, interfaces
+from cryptography.hazmat.primitives import hashes
 from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
 
 from ...utils import raises_unsupported_algorithm
 
 
-@utils.register_interface(interfaces.HashAlgorithm)
+@utils.register_interface(hashes.HashAlgorithm)
 class DummyHash(object):
     name = "dummy-hash"
     block_size = None