deprecate old from_encoded_point (#4640)

2 files changed, 10 insertions, 0 deletions

diff --git a/src/cryptography/hazmat/primitives/asymmetric/ec.py b/src/cryptography/hazmat/primitives/asymmetric/ec.py
index 6b1de7c5b..125235f8b 100644
--- a/src/cryptography/hazmat/primitives/asymmetric/ec.py
+++ b/src/cryptography/hazmat/primitives/asymmetric/ec.py
@@ -5,6 +5,7 @@
 from __future__ import absolute_import, division, print_function
 
 import abc
+import warnings
 
 import six
 
@@ -366,6 +367,14 @@ class EllipticCurvePublicNumbers(object):
         if not isinstance(curve, EllipticCurve):
             raise TypeError("curve must be an EllipticCurve instance")
 
+        warnings.warn(
+            "Support for unsafe construction of public numbers from "
+            "encoded data will be removed in a future version. "
+            "Please use EllipticCurvePublicKey.from_encoded_point",
+            utils.DeprecatedIn25,
+            stacklevel=2,
+        )
+
         if data.startswith(b'\x04'):
             # key_size is in bits. Convert to bytes and round up
             byte_length = (curve.key_size + 7) // 8
diff --git a/src/cryptography/utils.py b/src/cryptography/utils.py
index 65a4ee71b..cbbae3a79 100644
--- a/src/cryptography/utils.py
+++ b/src/cryptography/utils.py
@@ -23,6 +23,7 @@ class CryptographyDeprecationWarning(UserWarning):
 PersistentlyDeprecated = CryptographyDeprecationWarning
 DeprecatedIn21 = CryptographyDeprecationWarning
 DeprecatedIn23 = CryptographyDeprecationWarning
+DeprecatedIn25 = CryptographyDeprecationWarning
 
 
 def _check_bytes(name, value):