diff --git a/src/encoding/der/visitor/public-key-visitor.cpp b/src/encoding/der/visitor/public-key-visitor.cpp
index d5b6e3e..a2eab56 100644
--- a/src/encoding/der/visitor/public-key-visitor.cpp
+++ b/src/encoding/der/visitor/public-key-visitor.cpp
@@ -24,7 +24,7 @@
   DerNodePtrList& children = derSeq.getChildren();
 
   SimpleVisitor simpleVisitor;
-  shared_ptr<DerSequence> algoSeq = static_cast<shared_ptr<DerSequence> >(children[0]); 
+  shared_ptr<DerSequence> algoSeq = dynamic_pointer_cast<DerSequence>(children[0]); 
   OID algorithm = ndnboost::any_cast<OID>(algoSeq->getChildren()[0]->accept(simpleVisitor));  
   Blob raw = derSeq.getRaw();   
   return ndnboost::any(shared_ptr<PublicKey>(new PublicKey(algorithm, raw)));