diff --git a/src/security/validator-regex.cpp b/src/security/validator-regex.cpp
new file mode 100644
index 0000000..63c49c4
--- /dev/null
+++ b/src/security/validator-regex.cpp
@@ -0,0 +1,151 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/**
+ * Copyright (C) 2013 Regents of the University of California.
+ * @author: Yingdi Yu <yingdi@cs.ucla.edu>
+ * See COPYING for copyright and distribution information.
+ */
+
+#include "validator-regex.hpp"
+#include "signature-sha256-with-rsa.hpp"
+#include "certificate-cache-ttl.hpp"
+
+#include "../util/logging.hpp"
+
+INIT_LOGGER("ndn::ValidatorRegex");
+
+using namespace std;
+
+namespace ndn
+{
+
+const shared_ptr<CertificateCache> ValidatorRegex::DefaultCertificateCache = shared_ptr<CertificateCache>();
+
+ValidatorRegex::ValidatorRegex(shared_ptr<Face> face,
+                               shared_ptr<CertificateCache> certificateCache /* = DefaultCertificateCache */,
+                               const int stepLimit /* = 3 */)
+  : Validator(face)
+  , m_stepLimit(stepLimit)
+  , m_certificateCache(certificateCache)
+{
+  if(!static_cast<bool>(face))
+    throw Error("Face is not set!");
+
+  if(!static_cast<bool>(m_certificateCache))
+    m_certificateCache = make_shared<CertificateCacheTtl>(m_face->ioService());
+}
+
+void
+ValidatorRegex::onCertificateValidated(const shared_ptr<const Data> &signCertificate, 
+                                       const shared_ptr<const Data> &data, 
+                                       const OnDataValidated &onValidated, 
+                                       const OnDataValidationFailed &onValidationFailed)
+{
+  shared_ptr<IdentityCertificate> certificate = make_shared<IdentityCertificate>(*signCertificate);
+  
+  if(!certificate->isTooLate() && !certificate->isTooEarly())
+    {
+      m_certificateCache->insertCertificate(certificate);
+      
+      try{
+        if(verifySignature(*data, certificate->getPublicKeyInfo()))
+          {
+            onValidated(data);
+            return;
+          }
+      }catch(Signature::Error &e){
+        _LOG_DEBUG("ValidatorRegex Error: " << e.what());
+        onValidationFailed(data);
+        return;
+      }
+    }
+  else
+    {
+      _LOG_DEBUG("Wrong Invalidity: " << e.what());
+      onValidationFailed(data);
+      return;
+    }
+}
+
+void
+ValidatorRegex::onCertificateValidationFailed(const shared_ptr<const Data> &signCertificate, 
+                                              const shared_ptr<const Data> &data, 
+                                              const OnDataValidationFailed &onValidationFailed)
+{ onValidationFailed(data); }
+
+void
+ValidatorRegex::checkPolicy(const shared_ptr<const Data> &data, 
+                            int stepCount, 
+                            const OnDataValidated &onValidated, 
+                            const OnDataValidationFailed &onValidationFailed,
+                            vector<shared_ptr<ValidationRequest> > &nextSteps)
+{
+  if(m_stepLimit == stepCount){
+    _LOG_DEBUG("reach the maximum steps of verification");
+    onValidationFailed(data);
+    return;
+  }
+  
+  RuleList::iterator it = m_mustFailVerify.begin();
+  for(; it != m_mustFailVerify.end(); it++)
+    if((*it)->satisfy(*data))
+      {
+        onValidationFailed(data);
+        return;
+      }
+
+  it = m_verifyPolicies.begin();
+  for(; it != m_verifyPolicies.end(); it++)
+    {
+      if((*it)->satisfy(*data))
+        {
+          try{
+            SignatureSha256WithRsa sig(data->getSignature());                
+            
+            Name keyLocatorName = sig.getKeyLocator().getName();
+            shared_ptr<const Certificate> trustedCert;
+            if(m_trustAnchors.end() == m_trustAnchors.find(keyLocatorName))
+              trustedCert = m_certificateCache->getCertificate(keyLocatorName);
+            else
+              trustedCert = m_trustAnchors[keyLocatorName];
+            
+            if(static_cast<bool>(trustedCert)){
+              if(verifySignature(*data, sig, trustedCert->getPublicKeyInfo()))
+                onValidated(data);
+              else
+                onValidationFailed(data);
+              
+              return;
+            }
+            else{
+              // _LOG_DEBUG("KeyLocator is not trust anchor");                
+              OnDataValidated onKeyValidated = bind(&ValidatorRegex::onCertificateValidated, this, 
+                                                    _1, data, onValidated, onValidationFailed);
+              
+              OnDataValidationFailed onKeyValidationFailed = bind(&ValidatorRegex::onCertificateValidationFailed, this, 
+                                                                  _1, data, onValidationFailed);              
+
+              shared_ptr<ValidationRequest> nextStep = make_shared<ValidationRequest>(Interest(boost::cref(sig.getKeyLocator().getName())), 
+                                                                                      onKeyValidated,
+                                                                                      onKeyValidationFailed,
+                                                                                      3,
+                                                                                      stepCount + 1);
+              nextSteps.push_back(nextStep);
+              return;
+            }
+          }catch(SignatureSha256WithRsa::Error &e){
+            _LOG_DEBUG("ValidatorRegex Error: " << e.what());
+            onValidationFailed(data);
+            return;
+          }catch(KeyLocator::Error &e){
+            _LOG_DEBUG("ValidatorRegex Error: " << e.what());
+            onValidationFailed(data);
+            return;
+          }
+        }
+    }
+
+  onValidationFailed(data);
+  return;
+}
+
+}//ndn