diff --git a/src/detail/new-renew-revoke-encoder.hpp b/src/detail/new-renew-revoke-encoder.hpp
index 563e562..2b8e0e2 100644
--- a/src/detail/new-renew-revoke-encoder.hpp
+++ b/src/detail/new-renew-revoke-encoder.hpp
@@ -38,7 +38,7 @@
 Block
 encodeDataContent(const std::vector<uint8_t>& ecdhKey, const std::array<uint8_t, 32>& salt,
                   const RequestId& requestId, const Status& status,
-                  const std::list<std::string>& challenges);
+                  const std::vector<std::string>& challenges);
 
 std::list<std::string>
 decodeDataContent(const Block& content, std::vector<uint8_t>& ecdhKey,