Fixes #1327 -- adds multifernet
diff --git a/cryptography/fernet.py b/cryptography/fernet.py
index a8e0330..9fee3eb 100644
--- a/cryptography/fernet.py
+++ b/cryptography/fernet.py
@@ -127,3 +127,21 @@
except ValueError:
raise InvalidToken
return unpadded
+
+
+class MultiFernet(object):
+ def __init__(self, fernets):
+ if not fernets:
+ raise ValueError("MultiFernet requires at least one fernet")
+ self._fernets = fernets
+
+ def encrypt(self, msg):
+ return self._fernets[0].encrypt(msg)
+
+ def decrypt(self, msg, ttl=None):
+ for f in self._fernets:
+ try:
+ return f.decrypt(msg, ttl)
+ except InvalidToken:
+ pass
+ raise InvalidToken
diff --git a/tests/test_fernet.py b/tests/test_fernet.py
index 0b4e3e8..91af32a 100644
--- a/tests/test_fernet.py
+++ b/tests/test_fernet.py
@@ -24,7 +24,7 @@
import six
-from cryptography.fernet import Fernet, InvalidToken
+from cryptography.fernet import Fernet, InvalidToken, MultiFernet
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.ciphers import algorithms, modes
@@ -115,3 +115,34 @@
def test_bad_key(self, backend):
with pytest.raises(ValueError):
Fernet(base64.urlsafe_b64encode(b"abc"), backend=backend)
+
+
+@pytest.mark.supported(
+ only_if=lambda backend: backend.cipher_supported(
+ algorithms.AES("\x00" * 32), modes.CBC("\x00" * 16)
+ ),
+ skip_message="Does not support AES CBC",
+)
+class TestMultiFernet(object):
+ def test_encrypt(self, backend):
+ single_f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
+ f = MultiFernet([
+ single_f,
+ Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)
+ ])
+ assert single_f.decrypt(f.encrypt(b"abc")) == b"abc"
+
+ def test_decrypt(self, backend):
+ f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
+ f2 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
+ f = MultiFernet([f1, f2])
+
+ assert f.decrypt(f1.encrypt(b"abc")) == b"abc"
+ assert f.decrypt(f2.encrypt(b"abc")) == b"abc"
+
+ with pytest.raises(InvalidToken):
+ f.decrypt(b"\x00" * 16)
+
+ def test_no_fernets(self, backend):
+ with pytest.raises(ValueError):
+ MultiFernet([])