diff --git a/ndn-cpp/node.cpp b/ndn-cpp/node.cpp
index 2170fe9..7c7c5f0 100644
--- a/ndn-cpp/node.cpp
+++ b/ndn-cpp/node.cpp
@@ -8,6 +8,7 @@
 #include "c/encoding/binary-xml.h"
 #include "forwarding-entry.hpp"
 #include "security/key-chain.hpp"
+#include "sha256-with-rsa-signature.hpp"
 #include "node.hpp"
 
 using namespace std;
@@ -55,10 +56,11 @@
 
 void Node::NdndIdFetcher::operator()(const ptr_lib::shared_ptr<const Interest>& interest, const ptr_lib::shared_ptr<Data>& ndndIdData)
 {
-  if (ndndIdData->getSignature().getPublisherPublicKeyDigest().getPublisherPublicKeyDigest().size() > 0) {
+  Sha256WithRsaSignature *signature = dynamic_cast<Sha256WithRsaSignature*>(ndndIdData->getSignature());
+  if (signature && signature->getPublisherPublicKeyDigest().getPublisherPublicKeyDigest().size() > 0) {
     // Set the ndndId_ and continue.
     // TODO: If there are multiple connected hubs, the NDN ID is really stored per connected hub.
-    info_->node_.ndndId_ = ndndIdData->getSignature().getPublisherPublicKeyDigest().getPublisherPublicKeyDigest();
+    info_->node_.ndndId_ = signature->getPublisherPublicKeyDigest().getPublisherPublicKeyDigest();
     info_->node_.registerPrefixHelper(info_->prefix_, info_->onInterest_, info_->flags_);
   }
   // TODO: else need to log not getting the ndndId.