diff --git a/src/requester.hpp b/src/requester.hpp
index 65cf831..b3c7901 100644
--- a/src/requester.hpp
+++ b/src/requester.hpp
@@ -162,7 +162,7 @@
    * @throw std::runtime_error if the challenge is not selected or is not supported.
    */
   static shared_ptr<Interest>
-  genChallengeInterest(const RequesterState& state,
+  genChallengeInterest(RequesterState& state,
                        std::vector<std::tuple<std::string, std::string>>&& parameters);
 
   /**