Merge pull request #113 from mark-adams/fix-crypto-warnings

Fixed some DeprecationWarnings related to our cryptography 0.8 upgrade

Author: jpadilla

README.md

@@ -15,7 +15,7 @@ $ pip install PyJWT
 
 **A Note on Dependencies**:
 
-RSA and ECDSA signatures depend on the recommended `cryptography` package. If you plan on
+RSA and ECDSA signatures depend on the recommended `cryptography` package (0.8+). If you plan on
 using any of those algorithms, you'll need to install it as well.
 
 ```

jwt/algorithms.py

@@ -5,10 +5,16 @@
 from .exceptions import InvalidKeyError
 
 try:
-    from cryptography.hazmat.primitives import interfaces, hashes
+    from cryptography.hazmat.primitives import hashes
     from cryptography.hazmat.primitives.serialization import (
         load_pem_private_key, load_pem_public_key, load_ssh_public_key
     )
+    from cryptography.hazmat.primitives.asymmetric.rsa import (
+        RSAPrivateKey, RSAPublicKey
+    )
+    from cryptography.hazmat.primitives.asymmetric.ec import (
+        EllipticCurvePrivateKey, EllipticCurvePublicKey
+    )
     from cryptography.hazmat.primitives.asymmetric import ec, padding
     from cryptography.hazmat.backends import default_backend
     from cryptography.exceptions import InvalidSignature
@@ -142,8 +148,8 @@ def __init__(self, hash_alg):
             self.hash_alg = hash_alg()
 
         def prepare_key(self, key):
-            if isinstance(key, interfaces.RSAPrivateKey) or \
-               isinstance(key, interfaces.RSAPublicKey):
+            if isinstance(key, RSAPrivateKey) or \
+               isinstance(key, RSAPublicKey):
                 return key
 
             if isinstance(key, string_types):
@@ -199,8 +205,8 @@ def __init__(self, hash_alg):
             self.hash_alg = hash_alg()
 
         def prepare_key(self, key):
-            if isinstance(key, interfaces.EllipticCurvePrivateKey) or \
-               isinstance(key, interfaces.EllipticCurvePublicKey):
+            if isinstance(key, EllipticCurvePrivateKey) or \
+               isinstance(key, EllipticCurvePublicKey):
                 return key
 
             if isinstance(key, string_types):