Added Fernet encrypter.

Author: rohe

src/cryptojwt/jwe/fernet.py

@@ -0,0 +1,41 @@
+import base64
+import os
+from typing import Optional
+from typing import Union
+
+from cryptography.fernet import Fernet
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
+
+from cryptojwt import as_unicode
+from cryptojwt.jwe import Encrypter
+from cryptojwt.utils import as_bytes
+
+
+class FernetEncrypter(Encrypter):
+    def __init__(self, password: str, salt: Optional[bytes] = ""):
+        Encrypter.__init__(self)
+        if not salt:
+            salt = os.urandom(16)
+        else:
+            salt = as_bytes(salt)
+
+        kdf = PBKDF2HMAC(
+            algorithm=hashes.SHA256(),
+            length=32,
+            salt=salt,
+            iterations=390000)
+        self.key = base64.urlsafe_b64encode(kdf.derive(as_bytes(password)))
+        self.core = Fernet(self.key)
+
+    def encrypt(self, msg: Union[str, bytes], **kwargs) -> bytes:
+        text = as_bytes(msg)
+        # Padding to block size of AES
+        if len(text) % 16:
+            text += b" " * (16 - len(text) % 16)
+        return self.core.encrypt(as_bytes(text))
+
+    def decrypt(self, msg: Union[str, bytes], **kwargs) -> bytes:
+        dec_text = self.core.decrypt(as_bytes(msg))
+        dec_text = dec_text.rstrip(b" ")
+        return dec_text

src/cryptojwt/jws/jws.py

@@ -116,7 +116,7 @@ def sign_compact(self, keys=None, protected=None, **kwargs):
         key, xargs, _alg = self.alg_keys(keys, "sig", protected)
 
         if "typ" in self:
-            xargs["typ"] = self["typ"]
+            xargs["type"] = self["typ"]
 
         _headers.update(xargs)
         jwt = JWSig(**_headers)

tests/test_07_jwe.py

@@ -21,6 +21,7 @@
 from cryptojwt.jwe.exception import NoSuitableEncryptionKey
 from cryptojwt.jwe.exception import UnsupportedBitLength
 from cryptojwt.jwe.exception import WrongEncryptionAlgorithm
+from cryptojwt.jwe.fernet import FernetEncrypter
 from cryptojwt.jwe.jwe import JWE
 from cryptojwt.jwe.jwe import factory
 from cryptojwt.jwe.jwe_ec import JWE_EC
@@ -643,3 +644,14 @@ def test_invalid():
     decrypter = JWE(plain, alg="A128KW", enc="A128CBC-HS256")
     with pytest.raises(BadSyntax):
         decrypter.decrypt("a.b.c.d.e", keys=[encryption_key])
+
+
+def test_fernet():
+    encryption_key = SYMKey(use="enc", key="DukeofHazardpass", kid="some-key-id")
+
+    encrypter = FernetEncrypter(encryption_key.key)
+    _token = encrypter.encrypt(plain)
+
+    decrypter = encrypter
+    resp = decrypter.decrypt(_token)
+    assert resp == plain