diff --git a/src/chronos-invitation.cpp b/src/chronos-invitation.cpp
index b49c08b..b6084ab 100644
--- a/src/chronos-invitation.cpp
+++ b/src/chronos-invitation.cpp
@@ -10,7 +10,9 @@
 
 #include "chronos-invitation.h"
 
-#include <ndn-cpp/security/identity-certificate.hpp>
+#include <ndn-cpp-dev/security/identity-certificate.hpp>
+#include <ndn-cpp-dev/security/signature-sha256-with-rsa.hpp>
+
 #include "logging.h"
 
 using namespace std;
@@ -18,68 +20,95 @@
 
 INIT_LOGGER("ChronosInvitation");
 
-ChronosInvitation::ChronosInvitation(const ndn::Name& originalInterestName)
+
+const size_t ChronosInvitation::NAME_SIZE_MIN = 8;
+const size_t ChronosInvitation::INVITEE_START = 4;
+const ssize_t SIGNATURE      = -1;
+const ssize_t KEY_LOCATOR    = -2;
+const ssize_t INVITER_PREFIX = -3;
+const ssize_t CHATROOM       = -4;
+const Name ChronosInvitation::INVITATION_PREFIX("/ndn/broadcast/chronos/chat-invitation");
+
+
+ChronosInvitation::ChronosInvitation(const Name& originalInterestName)
   : m_interestName(originalInterestName)
 {
-  Name interestName = originalInterestName;
-  if(interestName.get(0).toEscapedString() != string("ndn")
-     || interestName.get(1).toEscapedString() != string("broadcast")
-     || interestName.get(2).toEscapedString() != string("chronos")
-     || interestName.get(3).toEscapedString() != string("invitation"))
-    throw Error("Wrong ChronosInvitation Name");
-    
-  int i = 4;
-  int size = interestName.size();
 
-  string chatroomStr("chatroom");
-  int inviteeBegin = 4;
-  for(; i < size; i++)
-    if(interestName.get(i).toEscapedString() == chatroomStr)
-      break;
+  size_t nameSize = originalInterestName.size();
 
-  if(i >= size)
-    throw Error("Wrong ChronosInvitation Name, No chatroom tag");
-  m_inviteeNameSpace = interestName.getSubName(inviteeBegin, i - inviteeBegin);
-
-  string inviterPrefixStr("inviter-prefix");
-  int chatroomBegin = (++i);
-  for(; i < size;  i++)
-    if(interestName.get(i).toEscapedString() == inviterPrefixStr)
-      break;
-
-  if(i > size)
-    throw Error("Wrong ChronosInvitation Name, No inviter-prefix tag");
-  m_chatroom = interestName.getSubName(chatroomBegin, i - chatroomBegin);
-
-  string inviterStr("inviter");
-  int inviterPrefixBegin = (++i);
-  for(; i < size; i++)
-    if(interestName.get(i).toEscapedString() == inviterStr)
-      break;
-  
-  if(i > size)
-    throw Error("Wrong ChronosInvitation Name, No inviter tag");
-  m_inviterPrefix = interestName.getSubName(inviterPrefixBegin, i - inviterPrefixBegin);
-
-  int inviterCertBegin = (++i);
-  m_inviterCertificateName = interestName.getSubName(inviterCertBegin, size - 1 - inviterCertBegin);
-  
-  m_signatureBits = interestName.get(-1).getValue();
+  if(nameSize < NAME_SIZE_MIN)
+    throw Error("Wrong ChronosInvitation Name: Wrong length"); 
  
-  Name keyName = IdentityCertificate::certificateNameToPublicKeyName(m_inviterCertificateName);
-  m_inviterNameSpace = keyName.getPrefix(-1);
+  if(!INVITATION_PREFIX.isPrefixOf(originalInterestName))
+    throw Error("Wrong ChronosInvitation Name: Wrong invitation prefix");
 
-  string signedName = interestName.getSubName(0, size - 1).toUri();
-  m_signedBlob = Buffer(signedName.c_str(), signedName.size());
+  //hack! should be more efficient.
+  Name signedName = originalInterestName.getPrefix(-1);
+  m_signedBlob = Buffer(signedName.wireEncode().value(), signedName.wireEncode().value_size());
+
+  Block signatureBlock(originalInterestName.get(SIGNATURE).getValue().buf(),
+                       originalInterestName.get(SIGNATURE).getValue().size());
+  Block signatureInfo(originalInterestName.get(KEY_LOCATOR).getValue().buf(),
+                      originalInterestName.get(KEY_LOCATOR).getValue().size());
+  m_signature = Signature(Signature(signatureInfo, signatureBlock));
+
+  SignatureSha256WithRsa sha256RsaSig(m_signature); 
+  m_inviterCertificateName = sha256RsaSig.getKeyLocator().getName();
+  
+  m_inviterNameSpace = IdentityCertificate::certificateNameToPublicKeyName(m_inviterCertificateName).getPrefix(-1);
+
+  m_inviterRoutingPrefix.wireDecode(Block(originalInterestName.get(INVITER_PREFIX).getValue().buf(),
+                                          originalInterestName.get(INVITER_PREFIX).getValue().size()));
+  
+  m_chatroom.wireDecode(Block(originalInterestName.get(CHATROOM).getValue().buf(),
+                              originalInterestName.get(CHATROOM).getValue().size()));
+
+  m_inviteeNameSpace = originalInterestName.getSubName(INVITEE_START, nameSize - NAME_SIZE_MIN);  
+  
+  m_isSigned = true;
+}
+
+ChronosInvitation::ChronosInvitation(const Name &inviteeNameSpace,
+                                     const Name &chatroom,
+                                     const Name &inviterRoutingPrefix,
+                                     const Name &inviterCertificateName)
+  : m_inviteeNameSpace(inviteeNameSpace)
+  , m_chatroom(chatroom)
+  , m_inviterRoutingPrefix(inviterRoutingPrefix)
+  , m_inviterCertificateName(inviterCertificateName)
+{
+  //implicit conversion, we do not keep version number in KeyLocator;
+  SignatureSha256WithRsa sha256RsaSig; 
+  sha256RsaSig.setKeyLocator(KeyLocator(inviterCertificateName.getPrefix(-1)));
+  m_signature.setInfo(sha256RsaSig.getInfo());
+  m_inviterNameSpace = IdentityCertificate::certificateNameToPublicKeyName(m_inviterCertificateName).getPrefix(-1);
+  
+  m_interestName = INVITATION_PREFIX;
+  m_interestName.append(inviteeNameSpace).append(chatroom.wireEncode()).append(inviterRoutingPrefix.wireEncode()).append(m_signature.getInfo());
+
+  m_signedBlob = Buffer(m_interestName.wireEncode().value(), m_interestName.wireEncode().value_size());
+  m_isSigned = false;
 }
 
 ChronosInvitation::ChronosInvitation(const ChronosInvitation& invitation)
   : m_interestName(invitation.m_interestName)
+  , m_signedBlob(invitation.m_signedBlob)
   , m_inviteeNameSpace(invitation.m_inviteeNameSpace)
   , m_chatroom(invitation.m_chatroom)
-  , m_inviterPrefix(invitation.m_inviterPrefix)
+  , m_inviterRoutingPrefix(invitation.m_inviterRoutingPrefix)
   , m_inviterCertificateName(invitation.m_inviterCertificateName)
-  , m_signatureBits(invitation.m_signatureBits)
+  , m_signature(invitation.m_signature)
   , m_inviterNameSpace(invitation.m_inviterNameSpace)
-  , m_signedBlob(invitation.m_signedBlob)
+  , m_isSigned(invitation.m_isSigned)
 {}
+
+void
+ChronosInvitation::setSignatureValue(const ndn::Block &signatureValue)
+{
+  if(m_isSigned)
+    return;
+
+  m_interestName.append(signatureValue);
+  m_signature.setValue(signatureValue);
+  m_isSigned = true;
+}