diff --git a/include/ndn-cpp/security/certificate/certificate-subject-description.hpp b/include/ndn-cpp/security/certificate/certificate-subject-description.hpp
index 30af6bf..9576e0d 100644
--- a/include/ndn-cpp/security/certificate/certificate-subject-description.hpp
+++ b/include/ndn-cpp/security/certificate/certificate-subject-description.hpp
@@ -12,42 +12,46 @@
 #include "../../common.hpp"
 #include "../../encoding/oid.hpp"
 
+namespace CryptoPP { class BufferedTransformation; }
+
 namespace ndn {
 
-namespace der { class DerNode; }
-  
 /**
  * A CertificateSubjectDescription represents the SubjectDescription entry in a Certificate.
  */
 class CertificateSubjectDescription {
 public:
-  /**
-   * Create a new CertificateSubjectDescription.
-   * @param oid The oid of the subject description entry.
-   * @param value The value of the subject description entry.
-   */
-  CertificateSubjectDescription(std::string oid, std::string value)
-  : oid_(oid), value_(value)
+  CertificateSubjectDescription(CryptoPP::BufferedTransformation &in)
   {
-  }
-
-  /**
-   * Create a new CertificateSubjectDescription.
-   * @param oid The oid of the subject description entry.
-   * @param value The value of the subject description entry.
-   */
-  CertificateSubjectDescription(OID oid, std::string value)
-  : oid_(oid), value_(value)
-  {
+    decode(in);
   }
   
   /**
-   * Encode the object into a DER syntax tree.
-   * @return The encoded DER syntax tree.
+   * Create a new CertificateSubjectDescription.
+   * @param oid The oid of the subject description entry.
+   * @param value The value of the subject description entry.
    */
-  ptr_lib::shared_ptr<der::DerNode> 
-  toDer() const;
+  CertificateSubjectDescription(const std::string &oid, const std::string &value)
+  : oid_(oid), value_(value)
+  {
+  }
 
+  /**
+   * Create a new CertificateSubjectDescription.
+   * @param oid The oid of the subject description entry.
+   * @param value The value of the subject description entry.
+   */
+  CertificateSubjectDescription(const OID &oid, const std::string &value)
+  : oid_(oid), value_(value)
+  {
+  }
+
+  void
+  encode(CryptoPP::BufferedTransformation &out) const;
+
+  void
+  decode(CryptoPP::BufferedTransformation &in);
+  
   std::string
   getOidString() const
   {