diff --git a/src/challenge/challenge-possession.cpp b/src/challenge/challenge-possession.cpp
index 7c2b30a..81a0bb6 100644
--- a/src/challenge/challenge-possession.cpp
+++ b/src/challenge/challenge-possession.cpp
@@ -229,7 +229,7 @@
 void
 ChallengePossession::fulfillParameters(std::multimap<std::string, std::string>& params,
                                        ndn::KeyChain& keyChain, const Name& issuedCertName,
-                                       const std::array<uint8_t, 16>& nonce)
+                                       ndn::span<const uint8_t, 16> nonce)
 {
   auto keyName = ndn::security::extractKeyNameFromCertName(issuedCertName);
   auto id = keyChain.getPib().getIdentity(ndn::security::extractIdentityFromCertName(issuedCertName));