EllipticCurveBackend interfaces

2 files changed, 87 insertions, 0 deletions

diff --git a/cryptography/hazmat/backends/interfaces.py b/cryptography/hazmat/backends/interfaces.py
index 55d5cd78..ba02bbd2 100644
--- a/cryptography/hazmat/backends/interfaces.py
+++ b/cryptography/hazmat/backends/interfaces.py
@@ -218,3 +218,39 @@ class CMACBackend(object):
         """
         Create a CMACContext for calculating a message authentication code.
         """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class EllipticCurveBackend(object):
+    @abc.abstractmethod
+    def elliptic_curve_signature_algorithm_supported(
+        self, signature_algorithm, curve
+    ):
+        """
+        Returns True if the backend supports the named elliptic curve with the
+        specified signature algorithm.
+        """
+
+    @abc.abstractmethod
+    def elliptic_curve_supported(self, curve):
+        """
+        Returns True if the backend supports the named elliptic curve.
+        """
+
+    @abc.abstractmethod
+    def generate_elliptic_curve_private_key(self, curve):
+        """
+        Return an object conforming to the EllipticCurvePrivateKey interface.
+        """
+
+    @abc.abstractmethod
+    def elliptic_curve_public_key_from_numbers(self, numbers):
+        """
+        Return an EllipticCurvePublicKey provider using the given numbers.
+        """
+
+    @abc.abstractmethod
+    def elliptic_curve_private_key_from_numbers(self, numbers):
+        """
+        Return an EllipticCurvePublicKey provider using the given numbers.
+        """
diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index 6f24f906..c1ce621a 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -476,3 +476,54 @@ A specific ``backend`` may provide one or more of these interfaces.
 
         :raises cryptography.exceptions.UnsupportedAlgorithm: If the data is
             encrypted with an unsupported algorithm.
+
+
+.. class:: EllipticCurveBackend
+
+    .. versionadded:: 0.5
+
+    .. method:: elliptic_curve_supported(curve)
+
+        :param curve: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.EllipticCurve`
+            provider.
+
+        :returns: True if the elliptic curve is supported by this backend.
+
+    .. method:: elliptic_curve_signature_algorithm_supported(signature_algorithm, curve)
+
+        :param signature_algorithm: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.EllipticCurveSignatureAlgorithm`
+            provider.
+
+        :param curve: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.EllipticCurve`
+            provider.
+
+        :returns: True if the signature algorithm and curve are supported by this backend.
+
+    .. method:: generate_elliptic_curve_private_key(curve)
+
+        :param curve: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.EllipticCurve`
+            provider.
+
+    .. method:: elliptic_curve_private_key_from_numbers(numbers)
+
+        :param numbers: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.EllipticCurvePrivateNumbers`
+            provider.
+
+        :returns: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.EllipticCurvePrivateKey`
+            provider.
+
+    .. method:: elliptic_curve_public_key_from_numbers(numbers)
+
+        :param numbers: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.EllipticCurvePublicNumbers`
+            provider.
+
+        :returns: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.EllipticCurvePublicKey`
+            provider.