diff --git a/CertTool/cert_tool.cpp b/CertTool/cert_tool.cpp
new file mode 100644
index 0000000..98c2f5c
--- /dev/null
+++ b/CertTool/cert_tool.cpp
@@ -0,0 +1,320 @@
+#include <ndn-cpp-dev/data.hpp>
+#include <ndn-cpp-dev/security/key-chain.hpp>
+#include <ndn-cpp-dev/util/random.hpp>
+#include <ndn-cpp-dev/security/identity-certificate.hpp>
+#include <ndn-cpp-dev/security/certificate-subject-description.hpp>
+#include <ndn-cpp-dev/security/signature-sha256-with-rsa.hpp>
+#include <ndn-cpp-dev/util/io.hpp>
+#include <boost/algorithm/string.hpp>
+#include <exception>
+
+
+
+
+namespace
+{
+
+    class CertTool: public ndn::KeyChain
+    {
+        typedef SecPublicInfo::Error InfoError;
+        typedef SecTpm::Error TpmError;
+    public:
+        CertTool()
+        {
+        }
+
+        std::pair<ndn::shared_ptr<ndn::IdentityCertificate> , bool>
+        getCertificate(ndn::Name certificateName)
+        {
+            try
+            {
+                ndn::shared_ptr<ndn::IdentityCertificate> cert=
+                                ndn::KeyChain::getCertificate(certificateName);
+                return std::make_pair(cert , true);
+            }
+            catch(TpmError& e)
+            {
+                std::cerr<<"Certificate Not Found"<<std::endl;
+                return std::make_pair(
+                        ndn::make_shared<ndn::IdentityCertificate>() , false);
+            }
+        }
+        
+
+        
+        /* Return Certificate Name */
+        ndn::Name
+        createIdentity(const ndn::Name identityName, const ndn::Name signee, 
+                                                            bool isUnSigned=false)
+        {
+            ndn::KeyChain::deleteIdentity(identityName);
+            ndn::KeyChain::addIdentity(identityName);
+            ndn::Name keyName;
+            try
+            {
+                keyName = ndn::KeyChain::getDefaultKeyNameForIdentity(identityName);
+            }
+            catch(InfoError& e)
+            {
+                keyName = ndn::KeyChain::generateRSAKeyPairAsDefault(identityName, true);
+            }
+            
+            ndn::shared_ptr<ndn::PublicKey> pubKey;
+            try
+            {
+                pubKey = ndn::KeyChain::getPublicKey(keyName);
+            }
+            catch(InfoError& e)
+            {
+                return identityName;
+            }
+            ndn::Name certName;
+            try
+            {
+                certName = ndn::KeyChain::getDefaultCertificateNameForKey(keyName);
+            }
+            catch(InfoError& e)
+            {
+                ndn::shared_ptr<ndn::IdentityCertificate> certificate =
+                    ndn::make_shared<ndn::IdentityCertificate>();
+                ndn::Name certificateName = keyName.getPrefix(-1);
+                certificateName.append("KEY").append(
+                    keyName.get(-1)).append("ID-CERT").appendVersion();
+                certificate->setName(certificateName);
+                certificate->setNotBefore(ndn::getNow());
+                certificate->setNotAfter(ndn::getNow() + 63072000 /* 2 years*/);
+                certificate->setPublicKeyInfo(*pubKey);
+                certificate->addSubjectDescription(
+                    ndn::CertificateSubjectDescription("2.5.4.41",
+                                                       keyName.toUri()));
+                certificate->encode();
+                if ( !isUnSigned )
+                {
+                    try
+                    {
+                        signByIdentity(*certificate,signee);
+                    }
+                    catch(InfoError& e)
+                    {
+                        try
+                        {
+                            ndn::KeyChain::deleteIdentity(identityName);
+                        }
+                        catch(InfoError& e)
+                        {
+                        }
+                        return identityName;
+                    }
+                    ndn::KeyChain::addCertificate(*(certificate));
+                }
+                
+                certName=certificate->getName();
+            }
+            return certName;
+        }
+        
+        template<typename T>
+        void 
+        signByIdentity(T& packet, const ndn::Name& identityName)
+        {
+            ndn::KeyChain::signByIdentity(packet,identityName);
+        }
+        
+        bool
+        loadCertificate(std::string inputFile)
+        {
+            ndn::shared_ptr<ndn::IdentityCertificate> cert = 
+                    ndn::io::load<ndn::IdentityCertificate>(
+                                           inputFile.c_str(), ndn::io::BASE_64);
+            
+            try
+            {
+                ndn::KeyChain::deleteCertificate(cert->getName());
+                ndn::KeyChain::addCertificate(*(cert));
+                return true;
+            }
+            catch(InfoError& e)
+            {
+                std::cout << e.what() <<std::endl;
+                return false;
+            }
+        }
+
+    };
+}
+
+
+void
+createCertificateAndDump(std::string identity, std::string signee, 
+                                                         std::string outputFile)
+{
+    ndn::Name certName;
+    CertTool ct;
+     
+        if( boost::iequals(signee, "self") || boost::iequals(signee, "unsigned"))
+        {
+            certName=ct.createIdentity(ndn::Name(identity),ndn::Name(identity));
+        }
+        else
+        {
+            certName=ct.createIdentity(ndn::Name(identity),ndn::Name(signee));
+        }
+    
+        std::pair<ndn::shared_ptr<ndn::IdentityCertificate> , bool> cert = 
+                                                    ct.getCertificate(certName);
+        if( cert.second )
+        {
+            std::cout<<*(cert.first)<<std::endl;
+            std::ofstream outFile(outputFile.c_str());
+            ndn::io::save(*(cert.first),outFile,ndn::io::BASE_64);
+        }
+        else
+        {
+            std::cerr<<"Certificate not created or signee not found"<<std::endl;
+        }
+    
+}
+
+void
+signCertificateAndDump(std::string signee,
+                                  std::string inputFile, std::string outputFile)
+{
+    ndn::shared_ptr<ndn::IdentityCertificate> cert = 
+                    ndn::io::load<ndn::IdentityCertificate>(
+                                           inputFile.c_str(), ndn::io::BASE_64);
+    try
+    {
+        CertTool ct;
+        ct.signByIdentity(*(cert), ndn::Name(signee));
+        std::cout<<*(cert)<<std::endl;
+        std::ofstream outFile(outputFile.c_str());
+        ndn::io::save(*(cert),outFile,ndn::io::BASE_64);
+        
+    }
+    catch(std::exception&  e)
+    {
+        std::cout << e.what() <<std::endl;
+    }
+    
+}
+
+void
+loadCertificate(std::string inputFile)
+{
+    try
+    {
+        CertTool ct;
+        if (ct.loadCertificate(inputFile) )
+        {
+            std::cout<<"Certificate Loaded in Key Chain"<<std::endl;
+        }
+    }
+    catch(std::exception&  e)
+    {
+        std::cout << e.what() <<std::endl;
+    }
+}
+
+
+static int
+usage(const std::string& program)
+{
+    std::cout << "Usage: " << program << " [OPTIONS...]"<<std::endl;
+    std::cout << "   Cert Tool options...." << std::endl;
+    std::cout << "       -(c|s|l) ,                  Create or Sign or Load identity's certificate" << std::endl;
+    std::cout << "       -i ,     --identityName     New/singing identity name" <<std::endl;
+    std::cout << "       -I ,     --signeeIdentity   Identity Name of signer or self for self signing or unsigned" <<std::endl;
+    std::cout << "       -f ,     --inputFile        Input file name for -s option"<<std::endl;
+    std::cout << "       -o ,     --outputFile       Output file name where certificate will be dumped"<<std::endl; 
+    std::cout << "       -h ,                        Display this help message" << std::endl;
+    exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv)
+{
+    bool isCreate=false;
+    bool isSign=false;
+    bool isLoad=false;
+    int operationCount=0;
+    std::string programName(argv[0]);
+    std::string inputFile;
+    std::string outputFile;
+    std::string identityName;
+    std::string signeeIdentityName;
+    int opt;
+    while ((opt = getopt(argc, argv, "cslf:I:i:f:o:h")) != -1)
+    {
+        switch (opt)
+        {
+            case 'c':
+                isCreate=true;
+                operationCount++;
+                break;
+            case 's':
+                isSign=true;
+                operationCount++;
+                break;
+            case 'l':
+                isLoad=true;
+                operationCount++;
+                break;
+            case 'f':
+                inputFile=optarg;
+                break;
+            case 'o':
+                outputFile=optarg;
+                break;
+            case 'i':
+                identityName=optarg;
+            case 'I':
+                signeeIdentityName=optarg;
+                break;
+            case 'h':
+            default:
+                usage(programName);
+                return EXIT_FAILURE;
+        }
+    }
+    
+    if( operationCount > 1)
+    {
+        std::cerr<<"Can not perform more than one operation at once !"<<std::endl;
+        usage(programName);
+    }
+    
+    if ( isCreate )
+    {
+        if ( identityName.empty() || 
+                            signeeIdentityName.empty() || outputFile.empty())
+        {
+           usage(programName); 
+        }
+        
+        createCertificateAndDump(identityName,signeeIdentityName, outputFile);
+    }
+    
+    if( isSign )
+    {
+        if ( signeeIdentityName.empty() || 
+                                        inputFile.empty() || outputFile.empty())
+        {
+           usage(programName); 
+        }
+        
+        signCertificateAndDump(signeeIdentityName, inputFile, outputFile);
+    }
+    
+    if( isLoad )
+    {
+        if ( inputFile.empty() )
+        {
+            usage(programName);
+        }
+        
+        loadCertificate(inputFile);
+        
+    }
+    
+    return EXIT_SUCCESS;
+}
+
diff --git a/CertTool/waf b/CertTool/waf
new file mode 100755
index 0000000..d45d28b
--- /dev/null
+++ b/CertTool/waf
Binary files differ
diff --git a/CertTool/wscript b/CertTool/wscript
new file mode 100644
index 0000000..facce9d
--- /dev/null
+++ b/CertTool/wscript
@@ -0,0 +1,67 @@
+# -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
+
+from waflib import Build, Logs, Utils, Task, TaskGen, Configure
+
+def options(opt):
+    opt.load('compiler_c compiler_cxx gnu_dirs c_osx cryptopp boost')
+    #opt.load('boost cryptopp', tooldir=['waf-tools'])
+
+    opt = opt.add_option_group('Certtool Options')
+    opt.add_option('--debug',action='store_true',default=False,dest='debug',help='''debugging mode''')
+    #opt.add_option('--without-osx-keychain', action='store_false', default=True, dest='with_osx_keychain',
+    #               help='''On Darwin, do not use OSX keychain as a default TPM''')
+
+def configure(conf):
+    conf.load("compiler_c compiler_cxx gnu_dirs c_osx cryptopp boost")
+
+    if conf.options.debug:
+        conf.define ('_DEBUG', 1)
+        flags = ['-O0',
+                 '-Wall',
+                 # '-Werror',
+                 '-Wno-unused-variable',
+                 '-g3',
+                 '-Wno-unused-private-field', # only clang supports
+                 '-fcolor-diagnostics',       # only clang supports
+                 '-Qunused-arguments',        # only clang supports
+                 '-Wno-tautological-compare', # suppress warnings from CryptoPP
+                 '-Wno-unused-function',      # another annoying warning from CryptoPP
+
+                 '-Wno-deprecated-declarations',
+                 ]
+
+        conf.add_supported_cxxflags (cxxflags = flags)
+    else:
+        flags = ['-O3', '-g', '-Wno-tautological-compare','-Wno-unused-variable',
+                         '-Wno-unused-function', '-Wno-deprecated-declarations']
+        conf.add_supported_cxxflags (cxxflags = flags)
+
+    conf.check_cfg(package='libndn-cpp-dev', args=['--cflags', '--libs'], uselib_store='NDN_CPP', mandatory=True)
+    conf.check_boost(lib='system iostreams thread unit_test_framework log', uselib_store='BOOST', version='1_55', mandatory=True)
+    conf.check_cfg(package='sqlite3', args=['--cflags', '--libs'], uselib_store='SQLITE3', mandatory=True)
+    conf.check_cryptopp(path=conf.options.cryptopp_dir, mandatory=True)
+    
+
+def build (bld):
+    bld (
+        features=['cxx', 'cxxprogram'],
+        target="certtool",
+        source = bld.path.ant_glob('*.cpp'),
+        use = 'NDN_CPP BOOST CRYPTOPP SQLITE3',
+        #includes = ". src"
+        )
+
+@Configure.conf
+def add_supported_cxxflags(self, cxxflags):
+    """
+    Check which cxxflags are supported by compiler and add them to env.CXXFLAGS variable
+    """
+    self.start_msg('Checking allowed flags for c++ compiler')
+
+    supportedFlags = []
+    for flag in cxxflags:
+        if self.check_cxx (cxxflags=[flag], mandatory=False):
+            supportedFlags += [flag]
+
+    self.end_msg (' '.join (supportedFlags))
+    self.env.CXXFLAGS += supportedFlags
diff --git a/src/security/nlsr_cert_store.cpp b/src/security/nlsr_cert_store.cpp
new file mode 100644
index 0000000..108d0c6
--- /dev/null
+++ b/src/security/nlsr_cert_store.cpp
@@ -0,0 +1,139 @@
+#include "nlsr_cert_store.hpp"
+
+namespace nlsr
+{
+    static bool
+    nlsrCertificateStoreEntryCompare(NlsrCertificateStoreEntry& ncse1,
+                                               NlsrCertificateStoreEntry& ncse2)
+    
+    {
+        return ncse1.getCert()->getName().toUri() == 
+                                          ncse2.getCert()->getName().toUri() ;
+    }
+    
+    static bool
+    nlsrCertificateStoreEntryCompareByName(NlsrCertificateStoreEntry& ncse1,
+                                               std::string compCertName)
+    
+    {
+        return ncse1.getCert()->getName().toUri() == compCertName ;
+    }
+    
+    bool
+    NlsrCertificateStore::addCertificate(NlsrCertificateStoreEntry & ncse)
+    {
+        std::list<NlsrCertificateStoreEntry>::iterator it = 
+                               std::find_if( certTable.begin(), certTable.end(),
+                             bind(&nlsrCertificateStoreEntryCompare, _1, ncse));
+        if(it == certTable.end())
+        {
+            certTable.push_back(ncse);
+            return true;
+        }
+        
+        if( it !=  certTable.end() )
+        {
+            if ( (*it).getCertSeqNum() < ncse.getCertSeqNum() )
+            {
+                certTable.erase(it);
+                certTable.push_back(ncse);
+                return true;
+            }
+        }
+        
+        return false;
+    }
+    
+    bool
+    NlsrCertificateStore::addCertificate(
+        ndn::shared_ptr<ndn::IdentityCertificate> pcert, uint32_t csn, bool isv)
+    {
+        NlsrCertificateStoreEntry ncse(pcert, csn, isv);
+        return addCertificate(ncse);
+    }
+    
+    std::pair<ndn::shared_ptr<ndn::IdentityCertificate>, bool>
+    NlsrCertificateStore::getCertificateFromStore(const std::string certName)
+    {
+        std::list<NlsrCertificateStoreEntry>::iterator it = 
+                               std::find_if( certTable.begin(), certTable.end(),
+                   bind(&nlsrCertificateStoreEntryCompareByName, _1, certName));
+        if(it == certTable.end())
+        {
+            ndn::shared_ptr<ndn::IdentityCertificate> cert=
+                                   ndn::make_shared<ndn::IdentityCertificate>();
+                                   
+            return std::make_pair(cert,false);
+        }
+        
+        return std::make_pair((*it).getCert(),true);
+    }
+    
+    std::pair<ndn::shared_ptr<ndn::IdentityCertificate>, bool>
+    NlsrCertificateStore::getCertificateFromStore(
+                                    const std::string certName, int checkSeqNum)
+    {
+        std::list<NlsrCertificateStoreEntry>::iterator it = 
+                               std::find_if( certTable.begin(), certTable.end(),
+                   bind(&nlsrCertificateStoreEntryCompareByName, _1, certName));
+        if(it == certTable.end())
+        {
+            ndn::shared_ptr<ndn::IdentityCertificate> cert=
+                                   ndn::make_shared<ndn::IdentityCertificate>();
+                                   
+            return std::make_pair(cert,false);
+        }
+        else
+        {
+            if( (*it).getCertSeqNum() == checkSeqNum )
+            {
+                return std::make_pair((*it).getCert(),true);
+            }
+        }
+           
+        return std::make_pair((*it).getCert(),false);
+        
+    }
+    
+    bool 
+    NlsrCertificateStore::isCertificateNewInStore(const std::string certName,
+                                                            int checkSeqNo)
+    {
+        std::list<NlsrCertificateStoreEntry>::iterator it = 
+                               std::find_if( certTable.begin(), certTable.end(),
+                   bind(&nlsrCertificateStoreEntryCompareByName, _1, certName));
+        if(it != certTable.end())
+        {
+            return (*it).getCertSeqNum() < checkSeqNo ;
+        }
+        
+        return true;
+        
+    }
+    
+    bool
+    NlsrCertificateStore::removeCertificateFromStroe(const std::string certName)
+    {
+        std::list<NlsrCertificateStoreEntry>::iterator it = 
+                               std::find_if( certTable.begin(), certTable.end(),
+                   bind(&nlsrCertificateStoreEntryCompareByName, _1, certName));
+        if(it != certTable.end())
+        {
+            certTable.erase(it);
+            return true;
+        }
+        
+        return false;
+    }
+    
+    void 
+    NlsrCertificateStore::printCertStore()
+    {
+        std::list<NlsrCertificateStoreEntry>::iterator it;
+        for(it=certTable.begin(); it!=certTable.end(); ++it)
+        {
+            std::cout<<(*it)<<std::endl;
+        }
+        
+    }
+}
diff --git a/src/security/nlsr_cse.cpp b/src/security/nlsr_cse.cpp
new file mode 100644
index 0000000..f52fdc9
--- /dev/null
+++ b/src/security/nlsr_cse.cpp
@@ -0,0 +1,18 @@
+#include <ndn-cpp-dev/security/signature-sha256-with-rsa.hpp>
+#include "nlsr_cse.hpp"
+
+namespace nlsr
+{
+    std::ostream&
+    operator <<(std::ostream& os, const NlsrCertificateStoreEntry& ncse)
+    {
+        os<<"------Certificate Entry---------------"<<std::endl;
+        os<<*(ncse.getCert())<<std::endl;
+        ndn::SignatureSha256WithRsa sig(ncse.getCert()->getSignature());
+        ndn::Name keyName=sig.getKeyLocator().getName();
+        os<<"Signee : "<<keyName.toUri()<<std::endl;
+        os<<"Cert Seq Num: "<<ncse.getCertSeqNum()<<std::endl;
+        os<<"Is Signer Verified: "<<ncse.getIsSignerVerified()<<std::endl;
+        return os;
+    }
+}
diff --git a/src/security/nlsr_cse.hpp b/src/security/nlsr_cse.hpp
new file mode 100644
index 0000000..27b992a
--- /dev/null
+++ b/src/security/nlsr_cse.hpp
@@ -0,0 +1,66 @@
+#ifndef NLSR_CERT_STORE_ENTRY_HPP
+#define NLSR_CERT_STORE_ENTRY_HPP
+
+#include <iostream>
+#include <ndn-cpp-dev/face.hpp>
+#include <ndn-cpp-dev/security/identity-certificate.hpp>
+
+namespace nlsr
+{
+    class NlsrCertificateStoreEntry
+    {
+      public:
+        NlsrCertificateStoreEntry()
+            : cert(ndn::make_shared<ndn::IdentityCertificate>())
+            , certSeqNum(0)
+            , isSignerVerified(false)
+        {}
+        
+        NlsrCertificateStoreEntry(ndn::shared_ptr<ndn::IdentityCertificate> pcert
+                                                       , uint32_t csn, bool isv)
+            : cert(pcert)
+            , certSeqNum(csn)
+            , isSignerVerified(isv)
+        {}
+        
+        ndn::shared_ptr<ndn::IdentityCertificate> getCert() const
+        {
+            return cert;
+        }
+        
+        void setCert(ndn::shared_ptr<ndn::IdentityCertificate> pcert)
+        {
+            cert=pcert;
+        }
+        
+        uint32_t getCertSeqNum() const
+        {
+            return certSeqNum;
+        }
+        
+        void setCertSeqNum(uint32_t csn)
+        {
+            certSeqNum=csn;
+        }
+        
+        bool getIsSignerVerified() const
+        {
+            return isSignerVerified;
+        }
+        
+        void setIsSignerVerified(bool isv)
+        {
+            isSignerVerified=isv;
+        }
+        
+      private:
+        ndn::shared_ptr<ndn::IdentityCertificate> cert;
+        uint32_t certSeqNum;
+        bool isSignerVerified;
+    };
+    /* Debugging Purpose */
+    std::ostream&
+    operator <<(std::ostream& os, const NlsrCertificateStoreEntry& ncse);
+}
+
+#endif