Der encoding: DerNode::accept is not const, so we need a list of non-const children.
diff --git a/src/encoding/der/visitor/print-visitor.cpp b/src/encoding/der/visitor/print-visitor.cpp
index 4c5ee64..80a4f5d 100644
--- a/src/encoding/der/visitor/print-visitor.cpp
+++ b/src/encoding/der/visitor/print-visitor.cpp
@@ -100,8 +100,8 @@
   
   printData(derSequence.getHeader(), indent);
 
-  const DerNodePtrList& children = derSequence.getChildren();
-  DerNodePtrList::const_iterator it = children.begin();
+  DerNodePtrList& children = derSequence.getChildren();
+  DerNodePtrList::iterator it = children.begin();
   for(; it != children.end(); it++)
   (*it)->accept(*this, indent + " | ");
 }