Data Packet Verification Added
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;
+        }
+        
+    }
+}