security: Add new v2::KeyChain

Change-Id: I5fdf51ecd96b50db2a7cbf730c6e8b1d9fbe09e9
Refs: #2926
diff --git a/src/security/pib/identity.cpp b/src/security/pib/identity.cpp
index 4797cb6..79cb090 100644
--- a/src/security/pib/identity.cpp
+++ b/src/security/pib/identity.cpp
@@ -40,13 +40,13 @@
 }
 
 Key
-Identity::addKey(const uint8_t* key, size_t keyLen, const Name& keyName)
+Identity::addKey(const uint8_t* key, size_t keyLen, const Name& keyName) const
 {
   return lock()->addKey(key, keyLen, keyName);
 }
 
 void
-Identity::removeKey(const Name& keyName)
+Identity::removeKey(const Name& keyName) const
 {
   return lock()->removeKey(keyName);
 }
@@ -64,13 +64,13 @@
 }
 
 const Key&
-Identity::setDefaultKey(const Name& keyName)
+Identity::setDefaultKey(const Name& keyName) const
 {
   return lock()->setDefaultKey(keyName);
 }
 
 const Key&
-Identity::setDefaultKey(const uint8_t* key, size_t keyLen, const Name& keyName)
+Identity::setDefaultKey(const uint8_t* key, size_t keyLen, const Name& keyName) const
 {
   return lock()->setDefaultKey(key, keyLen, keyName);
 }