diff --git a/cryptography/exceptions.py b/cryptography/exceptions.py
index d56db21..e9d8819 100644
--- a/cryptography/exceptions.py
+++ b/cryptography/exceptions.py
@@ -26,3 +26,7 @@
 
 class NotYetFinalized(Exception):
     pass
+
+
+class InvalidTag(Exception):
+    pass
diff --git a/cryptography/hazmat/bindings/openssl/backend.py b/cryptography/hazmat/bindings/openssl/backend.py
index fdb6762..527706b 100644
--- a/cryptography/hazmat/bindings/openssl/backend.py
+++ b/cryptography/hazmat/bindings/openssl/backend.py
@@ -19,7 +19,7 @@
 import cffi
 
 from cryptography import utils
-from cryptography.exceptions import UnsupportedAlgorithm
+from cryptography.exceptions import UnsupportedAlgorithm, InvalidTag
 from cryptography.hazmat.bindings.interfaces import (
     CipherBackend, HashBackend, HMACBackend
 )
@@ -200,7 +200,8 @@
 
     def _handle_error(self):
         code = self.lib.ERR_get_error()
-        assert code != 0
+        if not code:
+            raise InvalidTag
         lib = self.lib.ERR_GET_LIB(code)
         func = self.lib.ERR_GET_FUNC(code)
         reason = self.lib.ERR_GET_REASON(code)
diff --git a/tests/hazmat/primitives/utils.py b/tests/hazmat/primitives/utils.py
index 8df02e7..39f5ae8 100644
--- a/tests/hazmat/primitives/utils.py
+++ b/tests/hazmat/primitives/utils.py
@@ -7,7 +7,7 @@
 from cryptography.hazmat.primitives import hashes, hmac
 from cryptography.hazmat.primitives.ciphers import Cipher
 from cryptography.exceptions import (
-    AlreadyFinalized, NotYetFinalized, AlreadyUpdated,
+    AlreadyFinalized, NotYetFinalized, AlreadyUpdated, InvalidTag,
 )
 
 from ...utils import load_vectors_from_file
@@ -95,7 +95,7 @@
         decryptor = cipher.decryptor()
         decryptor.add_data(binascii.unhexlify(aad))
         actual_plaintext = decryptor.update(binascii.unhexlify(ciphertext))
-        with pytest.raises(AssertionError):
+        with pytest.raises(InvalidTag):
             decryptor.finalize()
     else:
         cipher = Cipher(