security: Include timestamp and nonce in signed interest and provide timestamp checking in ValidatorConf

Change-Id: I0adebd5c06b2d8d35ba13c5c03828b03334b7cec
Refs: #1642
diff --git a/src/security/key-chain.cpp b/src/security/key-chain.cpp
index 240bab6..22a25b3 100644
--- a/src/security/key-chain.cpp
+++ b/src/security/key-chain.cpp
@@ -41,6 +41,7 @@
 KeyChain::KeyChain()
   : m_pib(0)
   , m_tpm(0)
+  , m_lastTimestamp(time::toUnixTimestamp(time::system_clock::now()))
 {
 
   ConfigFile config;
@@ -102,6 +103,7 @@
                    const std::string& tpmName)
   : m_pib(0)
   , m_tpm(0)
+  , m_lastTimestamp(time::toUnixTimestamp(time::system_clock::now()))
 {
   if (pibName == "sqlite3")
     m_pib = new SecPublicInfoSqlite3;