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