diff --git a/triplesec/__init__.py b/triplesec/__init__.py
index 665e830..484cd44 100644
--- a/triplesec/__init__.py
+++ b/triplesec/__init__.py
@@ -103,7 +103,7 @@ def encrypt_ascii(self, data, key=None, v=None, extra_bytes=0,
                    "hqx": binascii.b2a_hqx}
         digestor = digests.get(digest)
         if not digestor:
-            TripleSecError(u"Digestor not supported.")
+            raise TripleSecError(u"Digestor not supported.")
 
         binary_result = self.encrypt(data, key, v, extra_bytes)
         result = digestor(binary_result)
@@ -180,7 +180,7 @@ def decrypt_ascii(self, ascii_string, key=None, digest="hex"):
                    "hqx": binascii.a2b_hqx}
         digestor = digests.get(digest)
         if not digestor:
-            TripleSecError(u"Digestor not supported.")
+            raise TripleSecError(u"Digestor not supported.")
 
         binary_string = digestor(ascii_string)
         result = self.decrypt(binary_string, key)