diff --git a/ndn-cpp/data.hpp b/ndn-cpp/data.hpp
index bca4507..cb0e559 100644
--- a/ndn-cpp/data.hpp
+++ b/ndn-cpp/data.hpp
@@ -8,82 +8,41 @@
 
 #include "common.hpp"
 #include "name.hpp"
-#include "publisher-public-key-digest.hpp"
 #include "key.hpp"
 #include "c/data.h"
 
 namespace ndn {
 
 /**
- * A Signature holds the signature bits and other info representing the signature in a data packet.
+ * A Signature is an abstract base class providing an methods to work with the signature information in a Data packet.
  */
 class Signature {
 public:
   /**
+   * Return a pointer to a new Signature which is a copy of this signature.
+   * This is pure virtual, the subclass must implement it.
+   */
+  virtual ptr_lib::shared_ptr<Signature> clone() const = 0;
+  
+  /**
+   * The virtual destructor.
+   */
+  virtual ~Signature();
+  
+    /**
    * Set the signatureStruct to point to the values in this signature object, without copying any memory.
    * WARNING: The resulting pointers in signatureStruct are invalid after a further use of this object which could reallocate memory.
+   * This is pure virtual, the subclass must implement it.
    * @param signatureStruct a C ndn_Signature struct where the name components array is already allocated.
    */
-  void get(struct ndn_Signature& signatureStruct) const;
+  virtual void get(struct ndn_Signature& signatureStruct) const = 0;
 
   /**
    * Clear this signature, and set the values by copying from the ndn_Signature struct.
+   * This is pure virtual, the subclass must implement it.
    * @param signatureStruct a C ndn_Signature struct
    */
-  void set(const struct ndn_Signature& signatureStruct);
-
-  const Blob& getDigestAlgorithm() const { return digestAlgorithm_; }
-
-  const Blob& getWitness() const { return witness_; }
-
-  const Blob& getSignature() const { return signature_; }
-  
-  const PublisherPublicKeyDigest& getPublisherPublicKeyDigest() const { return publisherPublicKeyDigest_; }
-  PublisherPublicKeyDigest& getPublisherPublicKeyDigest() { return publisherPublicKeyDigest_; }
-  
-  const KeyLocator& getKeyLocator() const { return keyLocator_; }
-  KeyLocator& getKeyLocator() { return keyLocator_; }
-
-  void setDigestAlgorithm(const std::vector<unsigned char>& digestAlgorithm) { digestAlgorithm_ = digestAlgorithm; }
-  void setDigestAlgorithm(const unsigned char *digestAlgorithm, unsigned int digestAlgorithmLength) 
-  { 
-    digestAlgorithm_ = Blob(digestAlgorithm, digestAlgorithmLength); 
-  }
-
-  void setWitness(const std::vector<unsigned char>& witness) { witness_ = witness; }
-  void setWitness(const unsigned char *witness, unsigned int witnessLength) 
-  { 
-    witness_ = Blob(witness, witnessLength); 
-  }
-
-  void setSignature(const std::vector<unsigned char>& signature) { signature_ = signature; }
-  void setSignature(const unsigned char *signature, unsigned int signatureLength) 
-  { 
-    signature_ = Blob(signature, signatureLength); 
-  }
-
-  void setPublisherPublicKeyDigest(const PublisherPublicKeyDigest& publisherPublicKeyDigest) { publisherPublicKeyDigest_ = publisherPublicKeyDigest; }
-  
-  void setKeyLocator(const KeyLocator& keyLocator) { keyLocator_ = keyLocator; }
-  
-  /**
-   * Clear all the fields.
-   */
-  void clear()
-  {
-    digestAlgorithm_.reset();
-    witness_.reset();
-    signature_.reset();
-    publisherPublicKeyDigest_.clear();
-    keyLocator_.clear();
-  }
-
-private:
-  Blob digestAlgorithm_; /**< if empty, the default is 2.16.840.1.101.3.4.2.1 (sha-256) */
-  Blob witness_;
-  Blob signature_;
-  PublisherPublicKeyDigest publisherPublicKeyDigest_;
-  KeyLocator keyLocator_;
+  virtual void set(const struct ndn_Signature& signatureStruct) = 0;
 };
 
 /**
@@ -139,14 +98,16 @@
   
 class Data {
 public:
-  Data() 
-  {
-  }
-  
-  Data(const Name& name)
-  : name_(name)
-  {
-  }
+  /**
+   * Create a new Data object with default values and where the signature is a blank Sha256WithRsaSignature.
+   */
+  Data();
+
+  /**
+   * Create a new Data object with the given name and default values and where the signature is a blank Sha256WithRsaSignature.
+   * @param name A reference to the name which is copied.
+   */
+  Data(const Name& name);
   
   Blob wireEncode(WireFormat& wireFormat = *WireFormat::getDefaultWireFormat()) const 
   {
@@ -174,8 +135,8 @@
    */
   void set(const struct ndn_Data& dataStruct);
 
-  const Signature& getSignature() const { return signature_; }
-  Signature& getSignature() { return signature_; }
+  const Signature* getSignature() const { return signature_.get(); }
+  Signature* getSignature() { return signature_.get(); }
   
   const Name& getName() const { return name_; }
   Name& getName() { return name_; }
@@ -185,7 +146,11 @@
   
   const Blob& getContent() const { return content_; }
 
-  void setSignature(const Signature& signature) { signature_ = signature; }
+  /**
+   * Set the signature to a copy of the given signature.
+   * @param signature The signature object which is cloned.
+   */
+  void setSignature(const Signature& signature) { signature_ = signature.clone(); }
   
   void setName(const Name& name) { name_ = name; }
   
@@ -210,7 +175,7 @@
   void setContent(const ptr_lib::shared_ptr<const std::vector<unsigned char> > &content) { content_ = content; }
 
 private:
-  Signature signature_;
+  ptr_lib::shared_ptr<Signature> signature_;
   Name name_;
   MetaInfo metaInfo_;
   Blob content_;