add convenience methods for key_size on EC{Public,Private}Key (#3587)

2 files changed, 21 insertions, 1 deletions

diff --git a/src/cryptography/hazmat/backends/openssl/ec.py b/src/cryptography/hazmat/backends/openssl/ec.py
index 68a35b21..3a81f919 100644
--- a/src/cryptography/hazmat/backends/openssl/ec.py
+++ b/src/cryptography/hazmat/backends/openssl/ec.py
@@ -135,6 +135,10 @@ class _EllipticCurvePrivateKey(object):
 
     curve = utils.read_only_property("_curve")
 
+    @property
+    def key_size(self):
+        return self.curve.key_size
+
     def signer(self, signature_algorithm):
         _check_signature_algorithm(signature_algorithm)
         return _ECDSASignatureContext(
@@ -231,6 +235,10 @@ class _EllipticCurvePublicKey(object):
 
     curve = utils.read_only_property("_curve")
 
+    @property
+    def key_size(self):
+        return self.curve.key_size
+
     def verifier(self, signature, signature_algorithm):
         if not isinstance(signature, bytes):
             raise TypeError("signature must be bytes.")
diff --git a/src/cryptography/hazmat/primitives/asymmetric/ec.py b/src/cryptography/hazmat/primitives/asymmetric/ec.py
index a527387b..7931b086 100644
--- a/src/cryptography/hazmat/primitives/asymmetric/ec.py
+++ b/src/cryptography/hazmat/primitives/asymmetric/ec.py
@@ -22,7 +22,7 @@ class EllipticCurve(object):
     @abc.abstractproperty
     def key_size(self):
         """
-        The bit length of the base point of the curve.
+        Bit size of a secret scalar for the curve.
         """
 
 
@@ -63,6 +63,12 @@ class EllipticCurvePrivateKey(object):
         """
 
     @abc.abstractproperty
+    def key_size(self):
+        """
+        Bit size of a secret scalar for the curve.
+        """
+
+    @abc.abstractproperty
     def sign(self, data, signature_algorithm):
         """
         Signs the data
@@ -98,6 +104,12 @@ class EllipticCurvePublicKey(object):
         The EllipticCurve that this key is on.
         """
 
+    @abc.abstractproperty
+    def key_size(self):
+        """
+        Bit size of a secret scalar for the curve.
+        """
+
     @abc.abstractmethod
     def public_numbers(self):
         """