diff --git a/model/ndn-content-object-header.cc b/model/ndn-content-object-header.cc
new file mode 100644
index 0000000..2a480d8
--- /dev/null
+++ b/model/ndn-content-object-header.cc
@@ -0,0 +1,554 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Ilya Moiseenko <iliamo@cs.ucla.edu>
+ *         Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "ndn-content-object-header.h"
+
+#include "ns3/log.h"
+#include "../helper/ndn-encoding-helper.h"
+#include "../helper/ndn-decoding-helper.h"
+
+#include "../helper/ccnb-parser/ccnb-parser-common.h"
+#include "../helper/ccnb-parser/visitors/ccnb-parser-void-depth-first-visitor.h"
+#include "../helper/ccnb-parser/visitors/ccnb-parser-name-components-visitor.h"
+#include "../helper/ccnb-parser/visitors/ccnb-parser-non-negative-integer-visitor.h"
+#include "../helper/ccnb-parser/visitors/ccnb-parser-timestamp-visitor.h"
+#include "../helper/ccnb-parser/visitors/ccnb-parser-string-visitor.h"
+#include "../helper/ccnb-parser/visitors/ccnb-parser-uint32t-blob-visitor.h"
+#include "../helper/ccnb-parser/visitors/ccnb-parser-content-type-visitor.h"
+
+#include "../helper/ccnb-parser/syntax-tree/ccnb-parser-block.h"
+#include "../helper/ccnb-parser/syntax-tree/ccnb-parser-dtag.h"
+
+#include <boost/foreach.hpp>
+
+NS_LOG_COMPONENT_DEFINE ("NdnContentObjectHeader");
+
+using namespace ns3::CcnbParser;
+
+namespace ns3
+{
+
+const std::string NdnContentObjectHeader::Signature::DefaultDigestAlgorithm = "2.16.840.1.101.3.4.2.1";
+
+NS_OBJECT_ENSURE_REGISTERED (NdnContentObjectHeader);
+NS_OBJECT_ENSURE_REGISTERED (NdnContentObjectTail);
+
+TypeId
+NdnContentObjectHeader::GetTypeId (void)
+{
+  static TypeId tid = TypeId ("ns3::NdnContentObjectHeader")
+    .SetGroupName ("ndn")
+    .SetParent<Header> ()
+    .AddConstructor<NdnContentObjectHeader> ()
+    ;
+  return tid;
+}
+
+NdnContentObjectHeader::NdnContentObjectHeader ()
+{
+}
+
+void
+NdnContentObjectHeader::SetName (const Ptr<NdnNameComponents> &name)
+{
+  m_name = name;
+}
+
+const NdnNameComponents&
+NdnContentObjectHeader::GetName () const
+{
+  if (m_name==0) throw NdnContentObjectHeaderException();
+  return *m_name;
+}
+
+Ptr<const NdnNameComponents>
+NdnContentObjectHeader::GetNamePtr () const
+{
+  return m_name;
+}
+
+#define CCNB NdnEncodingHelper // just to simplify writing
+
+void
+NdnContentObjectHeader::Serialize (Buffer::Iterator start) const
+{
+  size_t written = 0;
+  written += CCNB::AppendBlockHeader (start, CCN_DTAG_ContentObject, CcnbParser::CCN_DTAG); // <ContentObject>
+
+  // fake signature
+  written += CCNB::AppendBlockHeader (start, CCN_DTAG_Signature, CcnbParser::CCN_DTAG); // <Signature>
+  // Signature ::= √DigestAlgorithm? 
+  //               Witness?         
+  //               √SignatureBits
+  if (GetSignature ().GetDigestAlgorithm () != Signature::DefaultDigestAlgorithm)
+    {
+      written += CCNB::AppendString (start, CCN_DTAG_DigestAlgorithm, GetSignature ().GetDigestAlgorithm ());
+    }
+  written += CCNB::AppendTaggedBlob (start, CCN_DTAG_SignatureBits, GetSignature ().GetSignatureBits ()); // <SignatureBits />
+  written += CCNB::AppendCloser (start);                                    // </Signature>  
+
+  written += CCNB::AppendBlockHeader (start, CCN_DTAG_Name, CCN_DTAG);    // <Name>
+  written += CCNB::AppendNameComponents (start, GetName()); //   <Component>...</Component>...
+  written += CCNB::AppendCloser (start);                                  // </Name>  
+
+  // fake signature
+  written += CCNB::AppendBlockHeader (start, CCN_DTAG_SignedInfo, CCN_DTAG); // <SignedInfo>
+  // SignedInfo ::= √PublisherPublicKeyDigest
+  //                √Timestamp
+  //                √Type?
+  //                √FreshnessSeconds?
+  //                FinalBlockID?
+  //                KeyLocator?
+  written += CCNB::AppendTaggedBlob (start, CCN_DTAG_PublisherPublicKeyDigest,         // <PublisherPublicKeyDigest>...
+                                     GetSignedInfo ().GetPublisherPublicKeyDigest ());
+  
+  written += CCNB::AppendBlockHeader (start, CCN_DTAG_Timestamp, CCN_DTAG);            // <Timestamp>...
+  written += CCNB::AppendTimestampBlob (start, GetSignedInfo ().GetTimestamp ());
+  written += CCNB::AppendCloser (start);
+
+  if (GetSignedInfo ().GetContentType () != DATA)
+    {
+      uint8_t type[3];
+      type[0] = (GetSignedInfo ().GetContentType () >> 16) & 0xFF;
+      type[1] = (GetSignedInfo ().GetContentType () >> 8 ) & 0xFF;
+      type[2] = (GetSignedInfo ().GetContentType ()      ) & 0xFF;
+      
+      written += CCNB::AppendTaggedBlob (start, CCN_DTAG_Type, type, 3);
+    }
+  if (GetSignedInfo ().GetFreshness () > Seconds(0))
+    {
+      written += CCNB::AppendBlockHeader (start, CCN_DTAG_FreshnessSeconds, CCN_DTAG);
+      written += CCNB::AppendNumber (start, GetSignedInfo ().GetFreshness ().ToInteger (Time::S));
+      written += CCNB::AppendCloser (start);
+    }
+  if (GetSignedInfo ().GetKeyLocator () != 0)
+    {
+      written += CCNB::AppendBlockHeader (start, CCN_DTAG_KeyLocator, CCN_DTAG); // <KeyLocator>
+      {
+        written += CCNB::AppendBlockHeader (start, CCN_DTAG_KeyName, CCN_DTAG);    // <KeyName>
+        {
+          written += CCNB::AppendBlockHeader (start, CCN_DTAG_Name, CCN_DTAG);       // <Name>
+          written += CCNB::AppendNameComponents (start, GetName());                  //   <Component>...</Component>...
+          written += CCNB::AppendCloser (start);                                     // </Name>
+        }
+        written += CCNB::AppendCloser (start);                                     // </KeyName>
+      }
+      written += CCNB::AppendCloser (start);                                     // </KeyLocator>
+    }
+  
+  written += CCNB::AppendCloser (start);                                     // </SignedInfo>
+
+  written += CCNB::AppendBlockHeader (start, CCN_DTAG_Content, CCN_DTAG); // <Content>
+
+  // there are no closing tags !!!
+  // The closing tag is handled by NdnContentObjectTail
+}
+
+uint32_t
+NdnContentObjectHeader::GetSerializedSize () const
+{
+  size_t written = 0;
+  written += CCNB::EstimateBlockHeader (CCN_DTAG_ContentObject); // <ContentObject>
+
+  // fake signature
+  written += CCNB::EstimateBlockHeader (CCN_DTAG_Signature); // <Signature>
+  // Signature ::= DigestAlgorithm? 
+  //               Witness?         
+  //               SignatureBits   
+  if (GetSignature ().GetDigestAlgorithm () != Signature::DefaultDigestAlgorithm)
+    {
+      written += CCNB::EstimateString (CCN_DTAG_DigestAlgorithm, GetSignature ().GetDigestAlgorithm ());
+    }
+  written += CCNB::EstimateTaggedBlob (CCN_DTAG_SignatureBits,
+                                       sizeof (GetSignature ().GetSignatureBits ()));      // <SignatureBits />
+  written += 1;                                    // </Signature>  
+
+  written += CCNB::EstimateBlockHeader (CCN_DTAG_Name);    // <Name>
+  written += CCNB::EstimateNameComponents (GetName()); //   <Component>...</Component>...
+  written += 1;                                  // </Name>  
+
+  // fake signature
+  written += CCNB::EstimateBlockHeader (CCN_DTAG_SignedInfo); // <SignedInfo>
+  // SignedInfo ::= √PublisherPublicKeyDigest
+  //                √Timestamp
+  //                √Type?
+  //                √FreshnessSeconds?
+  //                FinalBlockID?
+  //                KeyLocator?
+  
+  written += CCNB::EstimateTaggedBlob (CCN_DTAG_PublisherPublicKeyDigest,                          // <PublisherPublicKeyDigest>...
+                                       sizeof (GetSignedInfo ().GetPublisherPublicKeyDigest ()));
+  
+  written += CCNB::EstimateBlockHeader (CCN_DTAG_Timestamp);                  // <Timestamp>...
+  written += CCNB::EstimateTimestampBlob (GetSignedInfo ().GetTimestamp ());
+  written += 1;
+
+  if (GetSignedInfo ().GetContentType () != DATA)
+    {
+      written += CCNB::EstimateTaggedBlob (CCN_DTAG_Type, 3);
+    }
+  if (GetSignedInfo ().GetFreshness () > Seconds(0))
+    {
+      written += CCNB::EstimateBlockHeader (CCN_DTAG_FreshnessSeconds);
+      written += CCNB::EstimateNumber (GetSignedInfo ().GetFreshness ().ToInteger (Time::S));
+      written += 1;
+    }
+
+  if (GetSignedInfo ().GetKeyLocator () != 0)
+    {
+      written += CCNB::EstimateBlockHeader (CCN_DTAG_KeyLocator); // <KeyLocator>
+      {
+        written += CCNB::EstimateBlockHeader (CCN_DTAG_KeyName);    // <KeyName>
+        {
+          written += CCNB::EstimateBlockHeader (CCN_DTAG_Name);       // <Name>
+          written += CCNB::EstimateNameComponents (GetName());        //   <Component>...</Component>...
+          written += 1;                                               // </Name>
+        }
+        written += 1;                                               // </KeyName>
+      }
+      written += 1;                                               // </KeyLocator>
+    }
+  
+  written += 1; // </SignedInfo>
+
+  written += CCNB::EstimateBlockHeader (CCN_DTAG_Content); // <Content>
+
+  // there are no closing tags !!!
+  // The closing tag is handled by NdnContentObjectTail
+  return written;
+}
+#undef CCNB
+
+class ContentObjectVisitor : public VoidDepthFirstVisitor
+{
+public:
+  virtual void visit (Dtag &n, boost::any param/*should be NdnContentObjectHeader* */)
+  {
+    // uint32_t n.m_dtag;
+    // std::list<Ptr<Block> > n.m_nestedBlocks;
+    static NameComponentsVisitor nameComponentsVisitor;
+    static NonNegativeIntegerVisitor nonNegativeIntegerVisitor;
+    static TimestampVisitor          timestampVisitor;
+    static StringVisitor     stringVisitor;
+    static Uint32tBlobVisitor uint32tBlobVisitor;
+    static ContentTypeVisitor contentTypeVisitor;
+  
+    NdnContentObjectHeader &contentObject = *(boost::any_cast<NdnContentObjectHeader*> (param));
+  
+    switch (n.m_dtag)
+      {
+      case CCN_DTAG_ContentObject:
+        // process nested blocks
+        BOOST_FOREACH (Ptr<Block> block, n.m_nestedTags)
+          {
+            block->accept (*this, param);
+          }
+        break;
+      case CCN_DTAG_Name:
+        {
+          // process name components
+          Ptr<NdnNameComponents> name = Create<NdnNameComponents> ();
+        
+          BOOST_FOREACH (Ptr<Block> block, n.m_nestedTags)
+            {
+              block->accept (nameComponentsVisitor, &(*name));
+            }
+          contentObject.SetName (name);
+          break;
+        }
+
+      case CCN_DTAG_Signature: 
+        // process nested blocks
+        BOOST_FOREACH (Ptr<Block> block, n.m_nestedTags)
+          {
+            block->accept (*this, param);
+          }      
+        break;
+
+      case CCN_DTAG_DigestAlgorithm:
+        NS_LOG_DEBUG ("DigestAlgorithm");
+        if (n.m_nestedTags.size ()!=1) // should be exactly one UDATA inside this tag
+          throw CcnbDecodingException ();
+        
+        contentObject.GetSignature ().SetDigestAlgorithm
+          (boost::any_cast<std::string> ((*n.m_nestedTags.begin())->accept
+                                         (stringVisitor)));
+        break;
+
+      case CCN_DTAG_SignatureBits:
+        NS_LOG_DEBUG ("SignatureBits");
+        if (n.m_nestedTags.size ()!=1) // should be only one nested tag
+          throw CcnbDecodingException ();
+
+        contentObject.GetSignature ().SetSignatureBits
+          (boost::any_cast<uint32_t> ((*n.m_nestedTags.begin())->accept
+                                      (uint32tBlobVisitor)));
+        break;
+
+      case CCN_DTAG_SignedInfo:
+        // process nested blocks
+        BOOST_FOREACH (Ptr<Block> block, n.m_nestedTags)
+          {
+            block->accept (*this, param);
+          }      
+        break;
+      
+      case CCN_DTAG_PublisherPublicKeyDigest:
+        NS_LOG_DEBUG ("PublisherPublicKeyDigest");
+        if (n.m_nestedTags.size ()!=1) // should be only one nested tag
+          throw CcnbDecodingException ();
+
+        contentObject.GetSignedInfo ().SetPublisherPublicKeyDigest
+          (boost::any_cast<uint32_t> ((*n.m_nestedTags.begin())->accept
+                                      (uint32tBlobVisitor)));
+        break;
+
+      case CCN_DTAG_Timestamp:
+        NS_LOG_DEBUG ("Timestamp");
+        if (n.m_nestedTags.size()!=1) // should be exactly one nested tag
+          throw CcnbDecodingException ();
+
+        contentObject.GetSignedInfo ().SetTimestamp
+          (boost::any_cast<Time> ((*n.m_nestedTags.begin())->accept
+                                  (timestampVisitor)));
+        break;
+
+      case CCN_DTAG_Type:
+        NS_LOG_DEBUG ("Type");
+        if (n.m_nestedTags.size ()!=1) // should be only one nested tag
+          throw CcnbDecodingException ();
+
+        contentObject.GetSignedInfo ().SetContentType
+          (static_cast<NdnContentObjectHeader::ContentType>
+           (boost::any_cast<uint32_t> ((*n.m_nestedTags.begin())->accept
+                                       (contentTypeVisitor))));
+        break;
+        
+      case CCN_DTAG_FreshnessSeconds:
+        NS_LOG_DEBUG ("FreshnessSeconds");
+      
+        if (n.m_nestedTags.size()!=1) // should be exactly one nested tag
+          throw CcnbDecodingException ();
+        
+        contentObject.GetSignedInfo ().SetFreshness
+          (Seconds
+           (boost::any_cast<uint32_t> ((*n.m_nestedTags.begin())->accept
+                                       (nonNegativeIntegerVisitor))));
+        break;
+      
+      case CCN_DTAG_KeyLocator:
+        // process nested blocks
+        BOOST_FOREACH (Ptr<Block> block, n.m_nestedTags)
+          {
+            block->accept (*this, param);
+          }      
+        break;
+
+      case CCN_DTAG_KeyName:
+        {
+          if (n.m_nestedTags.size ()!=1) // should be exactly one nested tag
+            throw CcnbDecodingException ();
+
+          Ptr<BaseTag> nameTag = DynamicCast<BaseTag>(n.m_nestedTags.front ());
+          if (nameTag == 0)
+            throw CcnbDecodingException ();
+
+          // process name components
+          Ptr<NdnNameComponents> name = Create<NdnNameComponents> ();
+        
+          BOOST_FOREACH (Ptr<Block> block, nameTag->m_nestedTags)
+            {
+              block->accept (nameComponentsVisitor, &(*name));
+            }
+          contentObject.GetSignedInfo ().SetKeyLocator (name);
+          break;
+        }
+
+      case CCN_DTAG_Content: // !!! HACK
+        // This hack was necessary for memory optimizations (i.e., content is virtual payload)
+        NS_ASSERT_MSG (n.m_nestedTags.size() == 0, "Parser should have stopped just after processing <Content> tag");
+        break;
+      
+      default: // ignore all other stuff
+        break;
+      }
+  }
+};
+
+uint32_t
+NdnContentObjectHeader::Deserialize (Buffer::Iterator start)
+{
+  static ContentObjectVisitor contentObjectVisitor;
+
+  Buffer::Iterator i = start;
+  Ptr<CcnbParser::Block> root = CcnbParser::Block::ParseBlock (i);
+  root->accept (contentObjectVisitor, this);
+
+  return i.GetDistanceFrom (start);
+}
+  
+TypeId
+NdnContentObjectHeader::GetInstanceTypeId (void) const
+{
+  return GetTypeId ();
+}
+  
+void
+NdnContentObjectHeader::Print (std::ostream &os) const
+{
+  os << "D: " << GetName ();
+  // os << "<ContentObject><Name>" << GetName () << "</Name><Content>";
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+NdnContentObjectTail::NdnContentObjectTail ()
+{
+}
+
+TypeId
+NdnContentObjectTail::GetTypeId (void)
+{
+  static TypeId tid = TypeId ("ns3::NdnContentObjectTail")
+    .SetParent<Trailer> ()
+    .AddConstructor<NdnContentObjectTail> ()
+    ;
+  return tid;
+}
+
+TypeId
+NdnContentObjectTail::GetInstanceTypeId (void) const
+{
+  return GetTypeId ();
+}
+
+void
+NdnContentObjectTail::Print (std::ostream &os) const
+{
+  os << "</Content></ContentObject>";
+}
+
+uint32_t
+NdnContentObjectTail::GetSerializedSize (void) const
+{
+  return 2;
+}
+
+void
+NdnContentObjectTail::Serialize (Buffer::Iterator start) const
+{
+  Buffer::Iterator i = start;
+  i.Prev (2); // Trailer interface requires us to go backwards
+  
+  i.WriteU8 (0x00); // </Content>
+  i.WriteU8 (0x00); // </ContentObject>
+}
+
+uint32_t
+NdnContentObjectTail::Deserialize (Buffer::Iterator start)
+{
+  Buffer::Iterator i = start;
+  i.Prev (2); // Trailer interface requires us to go backwards
+
+  uint8_t closing_tag_content = i.ReadU8 ();
+  NS_ASSERT_MSG (closing_tag_content==0, "Should be a closing tag </Content> (0x00)");
+
+  uint8_t closing_tag_content_object = i.ReadU8 ();
+  NS_ASSERT_MSG (closing_tag_content_object==0, "Should be a closing tag </ContentObject> (0x00)");
+
+  return 2;
+}
+
+///////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////
+
+NdnContentObjectHeader::SignedInfo::SignedInfo ()
+  : m_publisherPublicKeyDigest (0)
+  // ,  m_timestamp
+  , m_type (DATA)
+  // , m_freshness
+  // , FinalBlockID
+  // , KeyLocator
+{
+}
+
+void
+NdnContentObjectHeader::SignedInfo::SetPublisherPublicKeyDigest (uint32_t digest)
+{
+  m_publisherPublicKeyDigest = digest;
+}
+
+uint32_t
+NdnContentObjectHeader::SignedInfo::GetPublisherPublicKeyDigest () const
+{
+  return m_publisherPublicKeyDigest;
+}
+
+void
+NdnContentObjectHeader::SignedInfo::SetTimestamp (const Time &timestamp)
+{
+  m_timestamp = timestamp;
+}
+
+Time
+NdnContentObjectHeader::SignedInfo::GetTimestamp () const
+{
+  return m_timestamp;
+}
+
+void
+NdnContentObjectHeader::SignedInfo::SetContentType (NdnContentObjectHeader::ContentType type)
+{
+  m_type = type;
+}
+
+NdnContentObjectHeader::ContentType
+NdnContentObjectHeader::SignedInfo::GetContentType () const
+{
+  return m_type;
+}
+
+void
+NdnContentObjectHeader::SignedInfo::SetFreshness (const Time &freshness)
+{
+  m_freshness = freshness;
+}
+
+Time
+NdnContentObjectHeader::SignedInfo::GetFreshness () const
+{
+  return m_freshness;
+}
+
+void
+NdnContentObjectHeader::SignedInfo::SetKeyLocator (Ptr<const NdnNameComponents> keyLocator)
+{
+  m_keyLocator = keyLocator;
+}
+
+Ptr<const NdnNameComponents>
+NdnContentObjectHeader::SignedInfo::GetKeyLocator () const
+{
+  return m_keyLocator;
+}
+
+} // namespace ns3