diff --git a/src/public_include/decaf/shake.hxx b/src/public_include/decaf/shake.hxx
index e9ce45e..804f841 100644
--- a/src/public_include/decaf/shake.hxx
+++ b/src/public_include/decaf/shake.hxx
@@ -29,7 +29,7 @@ namespace decaf {
 
 /**
  * Hash function derived from Keccak
- * @todo throw exceptions when hash is misused.
+ * FUTURE: throw ProtocolException when hash is misused by calling update() after output().
  */
 class KeccakHash {
 protected: