deprecate signer/verifier on asymmetric keys (#3663)

* deprecate signer/verifier on asymmetric keys

* review feedback, switch deprecated_call to work around a bug

1 files changed, 4 insertions, 1 deletions

diff --git a/src/cryptography/hazmat/backends/openssl/ec.py b/src/cryptography/hazmat/backends/openssl/ec.py
index b70735dc..69da2344 100644
--- a/src/cryptography/hazmat/backends/openssl/ec.py
+++ b/src/cryptography/hazmat/backends/openssl/ec.py
@@ -9,7 +9,8 @@ from cryptography.exceptions import (
     InvalidSignature, UnsupportedAlgorithm, _Reasons
 )
 from cryptography.hazmat.backends.openssl.utils import (
-    _calculate_digest_and_algorithm, _check_not_prehashed
+    _calculate_digest_and_algorithm, _check_not_prehashed,
+    _warn_sign_verify_deprecated
 )
 from cryptography.hazmat.primitives import hashes, serialization
 from cryptography.hazmat.primitives.asymmetric import (
@@ -140,6 +141,7 @@ class _EllipticCurvePrivateKey(object):
         return self.curve.key_size
 
     def signer(self, signature_algorithm):
+        _warn_sign_verify_deprecated()
         _check_signature_algorithm(signature_algorithm)
         _check_not_prehashed(signature_algorithm.algorithm)
         return _ECDSASignatureContext(
@@ -241,6 +243,7 @@ class _EllipticCurvePublicKey(object):
         return self.curve.key_size
 
     def verifier(self, signature, signature_algorithm):
+        _warn_sign_verify_deprecated()
         if not isinstance(signature, bytes):
             raise TypeError("signature must be bytes.")