Merge pull request #1107 from public/ecdsa-multibackend

ECDSA multibackend

4 files changed, 161 insertions, 7 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 13c62de5..a38534d4 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -18,7 +18,7 @@ Changelog
   and
   :class:`~cryptography.hazmat.backends.interfaces.TraditionalOpenSSLSerializationBackend`
   support to the :doc:`/hazmat/backends/openssl`.
-
+* Added :class:`~cryptography.hazmat.backends.interfaces.EllipticCurveBackend`.
 
 0.4 - 2014-05-03
 ~~~~~~~~~~~~~~~~
diff --git a/cryptography/hazmat/backends/multibackend.py b/cryptography/hazmat/backends/multibackend.py
index f3c79376..27ab0636 100644
--- a/cryptography/hazmat/backends/multibackend.py
+++ b/cryptography/hazmat/backends/multibackend.py
@@ -16,8 +16,8 @@ from __future__ import absolute_import, division, print_function
 from cryptography import utils
 from cryptography.exceptions import UnsupportedAlgorithm, _Reasons
 from cryptography.hazmat.backends.interfaces import (
-    CMACBackend, CipherBackend, DSABackend, HMACBackend, HashBackend,
-    PBKDF2HMACBackend, RSABackend
+    CMACBackend, CipherBackend, DSABackend, EllipticCurveBackend, HMACBackend,
+    HashBackend, PBKDF2HMACBackend, RSABackend
 )
 
 
@@ -28,6 +28,7 @@ from cryptography.hazmat.backends.interfaces import (
 @utils.register_interface(PBKDF2HMACBackend)
 @utils.register_interface(RSABackend)
 @utils.register_interface(DSABackend)
+@utils.register_interface(EllipticCurveBackend)
 class MultiBackend(object):
     name = "multibackend"
 
@@ -243,3 +244,55 @@ class MultiBackend(object):
                 pass
         raise UnsupportedAlgorithm("This backend does not support CMAC.",
                                    _Reasons.UNSUPPORTED_CIPHER)
+
+    def elliptic_curve_supported(self, curve):
+        return any(
+            b.elliptic_curve_supported(curve)
+            for b in self._filtered_backends(EllipticCurveBackend)
+        )
+
+    def elliptic_curve_signature_algorithm_supported(
+        self, signature_algorithm, curve
+    ):
+        return any(
+            b.elliptic_curve_signature_algorithm_supported(
+                signature_algorithm, curve
+            )
+            for b in self._filtered_backends(EllipticCurveBackend)
+        )
+
+    def generate_elliptic_curve_private_key(self, curve):
+        for b in self._filtered_backends(EllipticCurveBackend):
+            try:
+                return b.generate_elliptic_curve_private_key(curve)
+            except UnsupportedAlgorithm:
+                continue
+
+        raise UnsupportedAlgorithm(
+            "This backend does not support this elliptic curve.",
+            _Reasons.UNSUPPORTED_ELLIPTIC_CURVE
+        )
+
+    def elliptic_curve_private_key_from_numbers(self, numbers):
+        for b in self._filtered_backends(EllipticCurveBackend):
+            try:
+                return b.elliptic_curve_private_key_from_numbers(numbers)
+            except UnsupportedAlgorithm:
+                continue
+
+        raise UnsupportedAlgorithm(
+            "This backend does not support this elliptic curve.",
+            _Reasons.UNSUPPORTED_ELLIPTIC_CURVE
+        )
+
+    def elliptic_curve_public_key_from_numbers(self, numbers):
+        for b in self._filtered_backends(EllipticCurveBackend):
+            try:
+                return b.elliptic_curve_public_key_from_numbers(numbers)
+            except UnsupportedAlgorithm:
+                continue
+
+        raise UnsupportedAlgorithm(
+            "This backend does not support this elliptic curve.",
+            _Reasons.UNSUPPORTED_ELLIPTIC_CURVE
+        )
diff --git a/docs/hazmat/primitives/asymmetric/ec.rst b/docs/hazmat/primitives/asymmetric/ec.rst
index 84911cba..3773e0ae 100644
--- a/docs/hazmat/primitives/asymmetric/ec.rst
+++ b/docs/hazmat/primitives/asymmetric/ec.rst
@@ -109,7 +109,7 @@ Elliptic Curve Signature Algorithms
         :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
         provider.
 
-    .. code-block:: pycon
+    .. doctest::
 
         >>> from cryptography.hazmat.backends import default_backend
         >>> from cryptography.hazmat.primitives import hashes
diff --git a/tests/hazmat/backends/test_multibackend.py b/tests/hazmat/backends/test_multibackend.py
index 93d58483..64dc062c 100644
--- a/tests/hazmat/backends/test_multibackend.py
+++ b/tests/hazmat/backends/test_multibackend.py
@@ -18,12 +18,12 @@ from cryptography.exceptions import (
     UnsupportedAlgorithm, _Reasons
 )
 from cryptography.hazmat.backends.interfaces import (
-    CMACBackend, CipherBackend, DSABackend, HMACBackend, HashBackend,
-    PBKDF2HMACBackend, RSABackend
+    CMACBackend, CipherBackend, DSABackend, EllipticCurveBackend, HMACBackend,
+    HashBackend, PBKDF2HMACBackend, RSABackend
 )
 from cryptography.hazmat.backends.multibackend import MultiBackend
 from cryptography.hazmat.primitives import cmac, hashes, hmac
-from cryptography.hazmat.primitives.asymmetric import padding
+from cryptography.hazmat.primitives.asymmetric import ec, padding
 from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
 
 from ...utils import raises_unsupported_algorithm
@@ -154,6 +154,41 @@ class DummyCMACBackend(object):
             raise UnsupportedAlgorithm("", _Reasons.UNSUPPORTED_CIPHER)
 
 
+@utils.register_interface(EllipticCurveBackend)
+class DummyEllipticCurveBackend(object):
+    def __init__(self, supported_curves):
+        self._curves = supported_curves
+
+    def elliptic_curve_supported(self, curve):
+        return any(
+            isinstance(curve, curve_type)
+            for curve_type in self._curves
+        )
+
+    def elliptic_curve_signature_algorithm_supported(
+        self, signature_algorithm, curve
+    ):
+        return (
+            isinstance(signature_algorithm, ec.ECDSA) and
+            any(
+                isinstance(curve, curve_type)
+                for curve_type in self._curves
+            )
+        )
+
+    def generate_elliptic_curve_private_key(self, curve):
+        if not self.elliptic_curve_supported(curve):
+            raise UnsupportedAlgorithm(_Reasons.UNSUPPORTED_ELLIPTIC_CURVE)
+
+    def elliptic_curve_private_key_from_numbers(self, numbers):
+        if not self.elliptic_curve_supported(numbers.public_numbers.curve):
+            raise UnsupportedAlgorithm(_Reasons.UNSUPPORTED_ELLIPTIC_CURVE)
+
+    def elliptic_curve_public_key_from_numbers(self, numbers):
+        if not self.elliptic_curve_supported(numbers.curve):
+            raise UnsupportedAlgorithm(_Reasons.UNSUPPORTED_ELLIPTIC_CURVE)
+
+
 class TestMultiBackend(object):
     def test_ciphers(self):
         backend = MultiBackend([
@@ -361,3 +396,69 @@ class TestMultiBackend(object):
 
         with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_CIPHER):
             cmac.CMAC(algorithms.TripleDES(fake_key), backend)
+
+    def test_elliptic_curve(self):
+        backend = MultiBackend([
+            DummyEllipticCurveBackend([
+                ec.SECT283K1
+            ])
+        ])
+
+        assert backend.elliptic_curve_supported(ec.SECT283K1()) is True
+
+        assert backend.elliptic_curve_signature_algorithm_supported(
+            ec.ECDSA(hashes.SHA256()),
+            ec.SECT283K1()
+        ) is True
+
+        backend.generate_elliptic_curve_private_key(ec.SECT283K1())
+
+        backend.elliptic_curve_private_key_from_numbers(
+            ec.EllipticCurvePrivateNumbers(
+                1,
+                ec.EllipticCurvePublicNumbers(
+                    2,
+                    3,
+                    ec.SECT283K1()
+                )
+            )
+        )
+
+        backend.elliptic_curve_public_key_from_numbers(
+            ec.EllipticCurvePublicNumbers(
+                2,
+                3,
+                ec.SECT283K1()
+            )
+        )
+
+        assert backend.elliptic_curve_supported(ec.SECT163K1()) is False
+
+        assert backend.elliptic_curve_signature_algorithm_supported(
+            ec.ECDSA(hashes.SHA256()),
+            ec.SECT163K1()
+        ) is False
+
+        with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_ELLIPTIC_CURVE):
+            backend.generate_elliptic_curve_private_key(ec.SECT163K1())
+
+        with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_ELLIPTIC_CURVE):
+            backend.elliptic_curve_private_key_from_numbers(
+                ec.EllipticCurvePrivateNumbers(
+                    1,
+                    ec.EllipticCurvePublicNumbers(
+                        2,
+                        3,
+                        ec.SECT163K1()
+                    )
+                )
+            )
+
+        with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_ELLIPTIC_CURVE):
+            backend.elliptic_curve_public_key_from_numbers(
+                ec.EllipticCurvePublicNumbers(
+                    2,
+                    3,
+                    ec.SECT163K1()
+                )
+            )