Merge pull request #1634 from public/deprecate-dsa

Move DSA* interfaces to interfaces.dsa module

10 files changed, 352 insertions, 294 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 5944b907..64a15f1f 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -10,6 +10,14 @@ Changelog
   now load elliptic curve public keys.
 * Added
   :func:`~cryptography.hazmat.primitives.asymmetric.rsa.rsa_recover_prime_factors`
+* :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`,
+  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParametersWithNumbers`,
+  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`,
+  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKeyWithNumbers`,
+  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey` and
+  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKeyWithNumbers`
+  were moved from :mod:`~cryptography.hazmat.primitives.interfaces` to
+  :mod:`~cryptography.hazmat.primitives.asymmetric.dsa`
 
 0.7.2 - 2015-01-16
 ~~~~~~~~~~~~~~~~~~
diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index 8efe2ce9..9afbcb67 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -306,17 +306,17 @@ A specific ``backend`` may provide one or more of these interfaces.
             restricted to only the 1024-bit keys specified in FIPS 186-2.
 
         :return: A new instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAParameters`
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`
             provider.
 
     .. method:: generate_dsa_private_key(parameters)
 
         :param parameters: A
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAParameters`
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`
             provider.
 
         :return: A new instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAPrivateKey`
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`
             provider.
 
         :raises ValueError: This is raised if the key size is not one of 1024,
@@ -366,7 +366,7 @@ A specific ``backend`` may provide one or more of these interfaces.
             :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameterNumbers`.
 
         :returns: A provider of
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAParameters`.
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`.
 
         :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised
             when any backend specific criteria are not met.
@@ -377,7 +377,7 @@ A specific ``backend`` may provide one or more of these interfaces.
             :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateNumbers`.
 
         :returns: A provider of
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAPrivateKey`.
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`.
 
         :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised
             when any backend specific criteria are not met.
@@ -388,7 +388,7 @@ A specific ``backend`` may provide one or more of these interfaces.
             :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicNumbers`.
 
         :returns: A provider of
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAPublicKey`.
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey`.
 
         :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised
             when any backend specific criteria are not met.
diff --git a/docs/hazmat/primitives/asymmetric/dsa.rst b/docs/hazmat/primitives/asymmetric/dsa.rst
index c2197d10..ff934a6a 100644
--- a/docs/hazmat/primitives/asymmetric/dsa.rst
+++ b/docs/hazmat/primitives/asymmetric/dsa.rst
@@ -28,7 +28,7 @@ Generation
         :class:`~cryptography.hazmat.backends.interfaces.DSABackend`
         provider.
 
-    :return: A :class:`~cryptography.hazmat.primitives.interfaces.DSAPrivateKey`
+    :return: A :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`
         provider.
 
     :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if
@@ -52,7 +52,7 @@ Generation
         :class:`~cryptography.hazmat.backends.interfaces.DSABackend`
         provider.
 
-    :return: A :class:`~cryptography.hazmat.primitives.interfaces.DSAParameters`
+    :return: A :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`
         provider.
 
     :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if
@@ -62,7 +62,7 @@ Generation
 Signing
 ~~~~~~~
 
-Using a :class:`~cryptography.hazmat.primitives.interfaces.DSAPrivateKey`
+Using a :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`
 provider.
 
 .. doctest::
@@ -86,7 +86,7 @@ described in :rfc:`6979`. This can be decoded using
 Verification
 ~~~~~~~~~~~~
 
-Using a :class:`~cryptography.hazmat.primitives.interfaces.DSAPublicKey`
+Using a :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey`
 provider.
 
 .. doctest::
@@ -136,7 +136,7 @@ Numbers
             provider.
 
         :returns: A new instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAParameters`
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`
             provider.
 
 .. class:: DSAPublicNumbers(y, parameter_numbers)
@@ -153,9 +153,9 @@ Numbers
 
     .. attribute:: parameter_numbers
 
-        :type: :class:`~cryptography.hazmat.primitives.dsa.DSAParameterNumbers`
+        :type: :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameterNumbers`
 
-        The :class:`~cryptography.hazmat.primitives.dsa.DSAParameterNumbers`
+        The :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameterNumbers`
         associated with the public key.
 
     .. method:: public_key(backend)
@@ -165,7 +165,7 @@ Numbers
             provider.
 
         :returns: A new instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAPublicKey`
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey`
             provider.
 
 .. class:: DSAPrivateNumbers(x, public_numbers)
@@ -187,9 +187,9 @@ Numbers
 
     .. attribute:: public_numbers
 
-        :type: :class:`~cryptography.hazmat.primitives.dsa.DSAPublicNumbers`
+        :type: :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicNumbers`
 
-        The :class:`~cryptography.hazmat.primitives.dsa.DSAPublicNumbers`
+        The :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicNumbers`
         associated with the private key.
 
     .. method:: private_key(backend)
@@ -199,9 +199,164 @@ Numbers
             provider.
 
         :returns: A new instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAPrivateKey`
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`
             provider.
 
+Key interfaces
+~~~~~~~~~~~~~~
+
+.. class:: DSAParameters
+
+    .. versionadded:: 0.3
+
+    `DSA`_ parameters.
+
+    .. method:: generate_private_key()
+
+        .. versionadded:: 0.5
+
+        Generate a DSA private key. This method can be used to generate many
+        new private keys from a single set of parameters.
+
+        :return: A
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`
+            provider.
+
+
+.. class:: DSAParametersWithNumbers
+
+    .. versionadded:: 0.5
+
+    Extends :class:`DSAParameters`.
+
+    .. method:: parameter_numbers()
+
+        Create a
+        :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameterNumbers`
+        object.
+
+        :returns: A
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameterNumbers`
+            instance.
+
+
+.. class:: DSAPrivateKey
+
+    .. versionadded:: 0.3
+
+    A `DSA`_ private key.
+
+    .. method:: public_key()
+
+        :return: :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey`
+
+        An DSA public key object corresponding to the values of the private key.
+
+    .. method:: parameters()
+
+        :return: :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`
+
+        The DSAParameters object associated with this private key.
+
+    .. method:: signer(algorithm, backend)
+
+        .. versionadded:: 0.4
+
+        Sign data which can be verified later by others using the public key.
+        The signature is formatted as DER-encoded bytes, as specified in
+        :rfc:`6979`.
+
+        :param algorithm: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            provider.
+
+        :param backend: A
+            :class:`~cryptography.hazmat.backends.interfaces.DSABackend`
+            provider.
+
+        :returns:
+            :class:`~cryptography.hazmat.primitives.interfaces.AsymmetricSignatureContext`
+
+    .. attribute:: key_size
+
+        :type: int
+
+        The bit length of the modulus.
+
+
+.. class:: DSAPrivateKeyWithNumbers
+
+    .. versionadded:: 0.5
+
+    Extends :class:`DSAPrivateKey`.
+
+    .. method:: private_numbers()
+
+        Create a
+        :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateNumbers`
+        object.
+
+        :returns: A
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateNumbers`
+            instance.
+
+
+.. class:: DSAPublicKey
+
+    .. versionadded:: 0.3
+
+    A `DSA`_ public key.
+
+    .. attribute:: key_size
+
+        :type: int
+
+        The bit length of the modulus.
+
+    .. method:: parameters()
+
+        :return: :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`
+
+        The DSAParameters object associated with this public key.
+
+    .. method:: verifier(signature, algorithm, backend)
+
+        .. versionadded:: 0.4
+
+        Verify data was signed by the private key associated with this public
+        key.
+
+        :param bytes signature: The signature to verify. DER encoded as
+            specified in :rfc:`6979`.
+
+        :param algorithm: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            provider.
+
+        :param backend: A
+            :class:`~cryptography.hazmat.backends.interfaces.DSABackend`
+            provider.
+
+        :returns:
+            :class:`~cryptography.hazmat.primitives.interfaces.AsymmetricVerificationContext`
+
+
+.. class:: DSAPublicKeyWithNumbers
+
+    .. versionadded:: 0.5
+
+    Extends :class:`DSAPublicKey`.
+
+    .. method:: public_numbers()
+
+        Create a
+        :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicNumbers`
+        object.
+
+        :returns: A
+            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicNumbers`
+            instance.
+
 
 .. _`DSA`: https://en.wikipedia.org/wiki/Digital_Signature_Algorithm
 .. _`public-key`: https://en.wikipedia.org/wiki/Public-key_cryptography
diff --git a/docs/hazmat/primitives/interfaces.rst b/docs/hazmat/primitives/interfaces.rst
index 2dea46d2..2ba140bd 100644
--- a/docs/hazmat/primitives/interfaces.rst
+++ b/docs/hazmat/primitives/interfaces.rst
@@ -273,162 +273,6 @@ RSA
             instance.
 
 
-DSA
-~~~
-
-.. class:: DSAParameters
-
-    .. versionadded:: 0.3
-
-    `DSA`_ parameters.
-
-    .. method:: generate_private_key()
-
-        .. versionadded:: 0.5
-
-        Generate a DSA private key. This method can be used to generate many
-        new private keys from a single set of parameters.
-
-        :return: A
-            :class:`~cryptography.hazmat.primitives.interfaces.DSAPrivateKey`
-            provider.
-
-
-.. class:: DSAParametersWithNumbers
-
-    .. versionadded:: 0.5
-
-    Extends :class:`DSAParameters`.
-
-    .. method:: parameter_numbers()
-
-        Create a
-        :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameterNumbers`
-        object.
-
-        :returns: A
-            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameterNumbers`
-            instance.
-
-
-.. class:: DSAPrivateKey
-
-    .. versionadded:: 0.3
-
-    A `DSA`_ private key.
-
-    .. method:: public_key()
-
-        :return: :class:`~cryptography.hazmat.primitives.interfaces.DSAPublicKey`
-
-        An DSA public key object corresponding to the values of the private key.
-
-    .. method:: parameters()
-
-        :return: :class:`~cryptography.hazmat.primitives.interfaces.DSAParameters`
-
-        The DSAParameters object associated with this private key.
-
-    .. method:: signer(algorithm, backend)
-
-        .. versionadded:: 0.4
-
-        Sign data which can be verified later by others using the public key.
-        The signature is formatted as DER-encoded bytes, as specified in
-        :rfc:`6979`.
-
-        :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
-            provider.
-
-        :param backend: A
-            :class:`~cryptography.hazmat.backends.interfaces.DSABackend`
-            provider.
-
-        :returns:
-            :class:`~cryptography.hazmat.primitives.interfaces.AsymmetricSignatureContext`
-
-    .. attribute:: key_size
-
-        :type: int
-
-        The bit length of the modulus.
-
-
-.. class:: DSAPrivateKeyWithNumbers
-
-    .. versionadded:: 0.5
-
-    Extends :class:`DSAPrivateKey`.
-
-    .. method:: private_numbers()
-
-        Create a
-        :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateNumbers`
-        object.
-
-        :returns: A
-            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateNumbers`
-            instance.
-
-
-.. class:: DSAPublicKey
-
-    .. versionadded:: 0.3
-
-    A `DSA`_ public key.
-
-    .. attribute:: key_size
-
-        :type: int
-
-        The bit length of the modulus.
-
-    .. method:: parameters()
-
-        :return: :class:`~cryptography.hazmat.primitives.interfaces.DSAParameters`
-
-        The DSAParameters object associated with this public key.
-
-    .. method:: verifier(signature, algorithm, backend)
-
-        .. versionadded:: 0.4
-
-        Verify data was signed by the private key associated with this public
-        key.
-
-        :param bytes signature: The signature to verify. DER encoded as
-            specified in :rfc:`6979`.
-
-        :param algorithm: An instance of a
-            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
-            provider.
-
-        :param backend: A
-            :class:`~cryptography.hazmat.backends.interfaces.DSABackend`
-            provider.
-
-        :returns:
-            :class:`~cryptography.hazmat.primitives.interfaces.AsymmetricVerificationContext`
-
-
-.. class:: DSAPublicKeyWithNumbers
-
-    .. versionadded:: 0.5
-
-    Extends :class:`DSAPublicKey`.
-
-    .. method:: public_numbers()
-
-        Create a
-        :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicNumbers`
-        object.
-
-        :returns: A
-            :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicNumbers`
-            instance.
-
-
 .. class:: EllipticCurve
 
     .. versionadded:: 0.5
diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py
index 34efdce9..75d7e32f 100644
--- a/src/cryptography/hazmat/backends/openssl/backend.py
+++ b/src/cryptography/hazmat/backends/openssl/backend.py
@@ -985,9 +985,6 @@ class Backend(object):
                 "Invalid EC key. Both x and y must be non-negative."
             )
 
-        bn_x = self._int_to_bn(x)
-        bn_y = self._int_to_bn(y)
-
         set_func, get_func, group = (
             self._ec_key_determine_group_get_set_funcs(ctx)
         )
@@ -996,6 +993,9 @@ class Backend(object):
         assert point != self._ffi.NULL
         point = self._ffi.gc(point, self._lib.EC_POINT_free)
 
+        bn_x = self._int_to_bn(x)
+        bn_y = self._int_to_bn(y)
+
         with self._tmp_bn_ctx() as bn_ctx:
             check_x = self._lib.BN_CTX_get(bn_ctx)
             check_y = self._lib.BN_CTX_get(bn_ctx)
@@ -1006,8 +1006,10 @@ class Backend(object):
             res = get_func(group, point, check_x, check_y, bn_ctx)
             assert res == 1
 
-            assert self._lib.BN_cmp(bn_x, check_x) == 0
-            assert self._lib.BN_cmp(bn_y, check_y) == 0
+            res = self._lib.BN_cmp(bn_x, check_x)
+            assert res == 0
+            res = self._lib.BN_cmp(bn_y, check_y)
+            assert res == 0
 
         res = self._lib.EC_KEY_set_public_key(ctx, point)
         assert res == 1
diff --git a/src/cryptography/hazmat/primitives/asymmetric/dsa.py b/src/cryptography/hazmat/primitives/asymmetric/dsa.py
index 9b06f3e6..58058df9 100644
--- a/src/cryptography/hazmat/primitives/asymmetric/dsa.py
+++ b/src/cryptography/hazmat/primitives/asymmetric/dsa.py
@@ -4,11 +4,97 @@
 
 from __future__ import absolute_import, division, print_function
 
+import abc
+
 import six
 
 from cryptography import utils
 
 
+@six.add_metaclass(abc.ABCMeta)
+class DSAParameters(object):
+    @abc.abstractmethod
+    def generate_private_key(self):
+        """
+        Generates and returns a DSAPrivateKey.
+        """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class DSAParametersWithNumbers(DSAParameters):
+    @abc.abstractmethod
+    def parameter_numbers(self):
+        """
+        Returns a DSAParameterNumbers.
+        """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class DSAPrivateKey(object):
+    @abc.abstractproperty
+    def key_size(self):
+        """
+        The bit length of the prime modulus.
+        """
+
+    @abc.abstractmethod
+    def public_key(self):
+        """
+        The DSAPublicKey associated with this private key.
+        """
+
+    @abc.abstractmethod
+    def parameters(self):
+        """
+        The DSAParameters object associated with this private key.
+        """
+
+    @abc.abstractmethod
+    def signer(self, signature_algorithm):
+        """
+        Returns an AsymmetricSignatureContext used for signing data.
+        """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class DSAPrivateKeyWithNumbers(DSAPrivateKey):
+    @abc.abstractmethod
+    def private_numbers(self):
+        """
+        Returns a DSAPrivateNumbers.
+        """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class DSAPublicKey(object):
+    @abc.abstractproperty
+    def key_size(self):
+        """
+        The bit length of the prime modulus.
+        """
+
+    @abc.abstractmethod
+    def parameters(self):
+        """
+        The DSAParameters object associated with this public key.
+        """
+
+    @abc.abstractmethod
+    def verifier(self, signature, signature_algorithm):
+        """
+        Returns an AsymmetricVerificationContext used for signing data.
+        """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class DSAPublicKeyWithNumbers(DSAPublicKey):
+    @abc.abstractmethod
+    def public_numbers(self):
+        """
+        Returns a DSAPublicNumbers.
+        """
+
+
 def generate_parameters(key_size, backend):
     return backend.generate_dsa_parameters(key_size)
 
diff --git a/src/cryptography/hazmat/primitives/interfaces/__init__.py b/src/cryptography/hazmat/primitives/interfaces/__init__.py
index fb5ceeae..7961cf15 100644
--- a/src/cryptography/hazmat/primitives/interfaces/__init__.py
+++ b/src/cryptography/hazmat/primitives/interfaces/__init__.py
@@ -8,10 +8,10 @@ import abc
 
 import six
 
-from cryptography.hazmat.primitives.interfaces.asymmetric.dsa import (
-    DSAParameters, DSAParametersWithNumbers, DSAPrivateKey,
-    DSAPrivateKeyWithNumbers, DSAPublicKey, DSAPublicKeyWithNumbers
-)
+from cryptography import utils
+
+from cryptography.hazmat.primitives.asymmetric import dsa
+
 from cryptography.hazmat.primitives.interfaces.asymmetric.ec import (
     EllipticCurve, EllipticCurvePrivateKey, EllipticCurvePrivateKeyWithNumbers,
     EllipticCurvePublicKey, EllipticCurvePublicKeyWithNumbers,
@@ -25,12 +25,6 @@ from cryptography.hazmat.primitives.interfaces.ciphers import (
 __all__ = [
     "BlockCipherAlgorithm",
     "CipherAlgorithm",
-    "DSAParameters",
-    "DSAParametersWithNumbers",
-    "DSAPrivateKey",
-    "DSAPrivateKeyWithNumbers",
-    "DSAPublicKey",
-    "DSAPublicKeyWithNumbers",
     "EllipticCurve",
     "EllipticCurvePrivateKey",
     "EllipticCurvePrivateKeyWithNumbers",
@@ -43,6 +37,66 @@ __all__ = [
     "ModeWithNonce"
 ]
 
+DSAParameters = utils.deprecated(
+    dsa.DSAParameters,
+    __name__,
+    (
+        "The DSAParameters interface has moved to the "
+        "cryptography.hazmat.primitives.asymmetric.dsa.module"
+    ),
+    utils.DeprecatedIn08
+)
+
+DSAParametersWithNumbers = utils.deprecated(
+    dsa.DSAParametersWithNumbers,
+    __name__,
+    (
+        "The DSAParametersWithNumbers interface has moved to the "
+        "cryptography.hazmat.primitives.asymmetric.dsa.module"
+    ),
+    utils.DeprecatedIn08
+)
+
+DSAPrivateKey = utils.deprecated(
+    dsa.DSAPrivateKey,
+    __name__,
+    (
+        "The DSAPrivateKey interface has moved to the "
+        "cryptography.hazmat.primitives.asymmetric.dsa.module"
+    ),
+    utils.DeprecatedIn08
+)
+
+DSAPrivateKeyWithNumbers = utils.deprecated(
+    dsa.DSAPrivateKeyWithNumbers,
+    __name__,
+    (
+        "The DSAPrivateKeyWithNumbers interface has moved to the "
+        "cryptography.hazmat.primitives.asymmetric.dsa.module"
+    ),
+    utils.DeprecatedIn08
+)
+
+DSAPublicKey = utils.deprecated(
+    dsa.DSAPublicKey,
+    __name__,
+    (
+        "The DSAPublicKeyWithNumbers interface has moved to the "
+        "cryptography.hazmat.primitives.asymmetric.dsa.module"
+    ),
+    utils.DeprecatedIn08
+)
+
+DSAPublicKeyWithNumbers = utils.deprecated(
+    dsa.DSAPublicKeyWithNumbers,
+    __name__,
+    (
+        "The DSAPublicKeyWithNumbers interface has moved to the "
+        "cryptography.hazmat.primitives.asymmetric.dsa.module"
+    ),
+    utils.DeprecatedIn08
+)
+
 
 @six.add_metaclass(abc.ABCMeta)
 class CipherContext(object):
diff --git a/src/cryptography/hazmat/primitives/interfaces/asymmetric/dsa.py b/src/cryptography/hazmat/primitives/interfaces/asymmetric/dsa.py
deleted file mode 100644
index acfc8973..00000000
--- a/src/cryptography/hazmat/primitives/interfaces/asymmetric/dsa.py
+++ /dev/null
@@ -1,93 +0,0 @@
-# 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
-
-
-@six.add_metaclass(abc.ABCMeta)
-class DSAParameters(object):
-    @abc.abstractmethod
-    def generate_private_key(self):
-        """
-        Generates and returns a DSAPrivateKey.
-        """
-
-
-@six.add_metaclass(abc.ABCMeta)
-class DSAParametersWithNumbers(DSAParameters):
-    @abc.abstractmethod
-    def parameter_numbers(self):
-        """
-        Returns a DSAParameterNumbers.
-        """
-
-
-@six.add_metaclass(abc.ABCMeta)
-class DSAPrivateKey(object):
-    @abc.abstractproperty
-    def key_size(self):
-        """
-        The bit length of the prime modulus.
-        """
-
-    @abc.abstractmethod
-    def public_key(self):
-        """
-        The DSAPublicKey associated with this private key.
-        """
-
-    @abc.abstractmethod
-    def parameters(self):
-        """
-        The DSAParameters object associated with this private key.
-        """
-
-    @abc.abstractmethod
-    def signer(self, signature_algorithm):
-        """
-        Returns an AsymmetricSignatureContext used for signing data.
-        """
-
-
-@six.add_metaclass(abc.ABCMeta)
-class DSAPrivateKeyWithNumbers(DSAPrivateKey):
-    @abc.abstractmethod
-    def private_numbers(self):
-        """
-        Returns a DSAPrivateNumbers.
-        """
-
-
-@six.add_metaclass(abc.ABCMeta)
-class DSAPublicKey(object):
-    @abc.abstractproperty
-    def key_size(self):
-        """
-        The bit length of the prime modulus.
-        """
-
-    @abc.abstractmethod
-    def parameters(self):
-        """
-        The DSAParameters object associated with this public key.
-        """
-
-    @abc.abstractmethod
-    def verifier(self, signature, signature_algorithm):
-        """
-        Returns an AsymmetricVerificationContext used for signing data.
-        """
-
-
-@six.add_metaclass(abc.ABCMeta)
-class DSAPublicKeyWithNumbers(DSAPublicKey):
-    @abc.abstractmethod
-    def public_numbers(self):
-        """
-        Returns a DSAPublicNumbers.
-        """
diff --git a/src/cryptography/utils.py b/src/cryptography/utils.py
index 72f9a347..78dcc1ca 100644
--- a/src/cryptography/utils.py
+++ b/src/cryptography/utils.py
@@ -13,6 +13,8 @@ import warnings
 # DeprecatedIn07 objects exist. This comment exists to remind developers to
 # look for them when it's time for the ninth release cycle deprecation dance.
 
+DeprecatedIn08 = PendingDeprecationWarning
+
 
 def read_only_property(name):
     return property(lambda self: getattr(self, name))
diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py
index b6bb5491..5b5c7bd7 100644
--- a/tests/hazmat/backends/test_openssl.py
+++ b/tests/hazmat/backends/test_openssl.py
@@ -249,19 +249,6 @@ class TestOpenSSLRandomEngine(object):
         assert res == 1
         assert backend._ffi.buffer(buf)[:] != "\x00" * 500
 
-    def test_activate_osrandom_already_default(self):
-        e = backend._lib.ENGINE_get_default_RAND()
-        name = backend._lib.ENGINE_get_name(e)
-        assert name == backend._lib.Cryptography_osrandom_engine_name
-        res = backend._lib.ENGINE_free(e)
-        assert res == 1
-        backend.activate_osrandom_engine()
-        e = backend._lib.ENGINE_get_default_RAND()
-        name = backend._lib.ENGINE_get_name(e)
-        assert name == backend._lib.Cryptography_osrandom_engine_name
-        res = backend._lib.ENGINE_free(e)
-        assert res == 1
-
     def test_activate_osrandom_no_default(self):
         backend.activate_builtin_random()
         e = backend._lib.ENGINE_get_default_RAND()
@@ -292,6 +279,19 @@ class TestOpenSSLRandomEngine(object):
         e = backend._lib.ENGINE_get_default_RAND()
         assert e == backend._ffi.NULL
 
+    def test_activate_osrandom_already_default(self):
+        e = backend._lib.ENGINE_get_default_RAND()
+        name = backend._lib.ENGINE_get_name(e)
+        assert name == backend._lib.Cryptography_osrandom_engine_name
+        res = backend._lib.ENGINE_free(e)
+        assert res == 1
+        backend.activate_osrandom_engine()
+        e = backend._lib.ENGINE_get_default_RAND()
+        name = backend._lib.ENGINE_get_name(e)
+        assert name == backend._lib.Cryptography_osrandom_engine_name
+        res = backend._lib.ENGINE_free(e)
+        assert res == 1
+
 
 class TestOpenSSLRSA(object):
     def test_generate_rsa_parameters_supported(self):