diff --git a/ndn-cpp/security/certificate/certificate.cpp b/ndn-cpp/security/certificate/certificate.cpp
index 9a01424..a1acfbf 100644
--- a/ndn-cpp/security/certificate/certificate.cpp
+++ b/ndn-cpp/security/certificate/certificate.cpp
@@ -45,7 +45,7 @@
 bool
 Certificate::isTooEarly()
 {
-  Time now = ndn_getNowMilliseconds();
+  MillisecondsSince1970 now = ndn_getNowMilliseconds();
   if(now < notBefore_)
     return true;
   else
@@ -55,7 +55,7 @@
 bool 
 Certificate::isTooLate()
 {
-  Time now = ndn_getNowMilliseconds();
+  MillisecondsSince1970 now = ndn_getNowMilliseconds();
   if(now > notAfter_)
     return true;
   else
diff --git a/ndn-cpp/security/identity/identity-manager.cpp b/ndn-cpp/security/identity/identity-manager.cpp
index f5b4657..c5a7793 100644
--- a/ndn-cpp/security/identity/identity-manager.cpp
+++ b/ndn-cpp/security/identity/identity-manager.cpp
@@ -82,7 +82,7 @@
 }
 
 Name
-IdentityManager::createIdentityCertificate(const Name& keyName, const Name& signerCertificateName, const Time& notBefore, const Time& notAfter)
+IdentityManager::createIdentityCertificate(const Name& keyName, const Name& signerCertificateName, const MillisecondsSince1970& notBefore, const MillisecondsSince1970& notAfter)
 {
   Blob keyBlob = identityStorage_->getKey(keyName);
   shared_ptr<PublicKey> publicKey = PublicKey::fromDer(keyBlob);
@@ -97,7 +97,7 @@
 
 ptr_lib::shared_ptr<IdentityCertificate>
 IdentityManager::createIdentityCertificate
-  (const Name& keyName, const PublicKey& publicKey, const Name& signerCertificateName, const Time& notBefore, const Time& notAfter)
+  (const Name& keyName, const PublicKey& publicKey, const Name& signerCertificateName, const MillisecondsSince1970& notBefore, const MillisecondsSince1970& notAfter)
 {
 #if 0
   shared_ptr<IdentityCertificate> certificate(new IdentityCertificate());
@@ -236,9 +236,9 @@
   current.tm_hour = 0;
   current.tm_min  = 0;
   current.tm_sec  = 0;
-  Time notBefore = boost::posix_time::ptime_from_tm(current);
+  MillisecondsSince1970 notBefore = boost::posix_time::ptime_from_tm(current);
   current.tm_year = current.tm_year + 20;
-  Time notAfter = boost::posix_time::ptime_from_tm(current);
+  MillisecondsSince1970 notAfter = boost::posix_time::ptime_from_tm(current);
 
   certificate->setNotBefore(notBefore);
   certificate->setNotAfter(notAfter);