diff --git a/include/ndn-cpp/security/identity/memory-identity-storage.hpp b/include/ndn-cpp/security/identity/sec-public-info-memory.hpp
similarity index 84%
rename from include/ndn-cpp/security/identity/memory-identity-storage.hpp
rename to include/ndn-cpp/security/identity/sec-public-info-memory.hpp
index 57f8050..734d4d7 100644
--- a/include/ndn-cpp/security/identity/memory-identity-storage.hpp
+++ b/include/ndn-cpp/security/identity/sec-public-info-memory.hpp
@@ -5,29 +5,29 @@
  * See COPYING for copyright and distribution information.
  */
 
-#ifndef NDN_MEMORY_IDENTITY_STORAGE_HPP
-#define NDN_MEMORY_IDENTITY_STORAGE_HPP
+#ifndef NDN_SEC_PUBLIC_INFO_MEMORY_HPP
+#define NDN_SEC_PUBLIC_INFO_MEMORY_HPP
 
 #include <vector>
 #include <map>
-#include "identity-storage.hpp"
+#include "sec-public-info.hpp"
 
 namespace ndn {
 
 /**
- * MemoryIdentityStorage extends IdentityStorage and implements its methods to store identity, public key and certificate objects in memory.
- * The application must get the objects through its own means and add the objects to the MemoryIdentityStorage object.
- * To use permanent file-based storage, see BasicIdentityStorage.
+ * MemoryKeyMetaInfo extends IdentityStorage and implements its methods to store identity, public key and certificate objects in memory.
+ * The application must get the objects through its own means and add the objects to the MemoryKeyMetaInfo object.
+ * To use permanent file-based storage, see BasicKeyMetaInfo.
  */
-class MemoryIdentityStorage : public IdentityStorage {
+class SecPublicInfoMemory : public SecPublicInfo {
 public:
-  struct Error : public std::runtime_error { Error(const std::string &what) : std::runtime_error(what) {} };
+  struct Error : public SecPublicInfo::Error { Error(const std::string &what) : SecPublicInfo::Error(what) {} };
 
   /**
    * The virtual Destructor.
    */
   virtual 
-  ~MemoryIdentityStorage();
+  ~SecPublicInfoMemory();
 
   /**
    * Check if the specified identity already exists.
@@ -57,7 +57,7 @@
    * @return true if the key exists, otherwise false.
    */
   virtual bool 
-  doesKeyExist(const Name& keyName);
+  doesPublicKeyExist(const Name& keyName);
 
   /**
    * Add a public key to the identity storage.
@@ -66,7 +66,7 @@
    * @param publicKeyDer A blob of the public key DER to be added.
    */
   virtual void 
-  addKey(const Name& keyName, KeyType keyType, const PublicKey& publicKeyDer);
+  addPublicKey(const Name& keyName, KeyType keyType, const PublicKey& publicKeyDer);
 
   /**
    * Get the public key DER blob from the identity storage.
@@ -74,21 +74,21 @@
    * @return The DER Blob.  If not found, return a Blob with a null pointer.
    */
   virtual ptr_lib::shared_ptr<PublicKey>
-  getKey(const Name& keyName);
+  getPublicKey(const Name& keyName);
 
   /**
    * Activate a key.  If a key is marked as inactive, its private part will not be used in packet signing.
    * @param keyName name of the key
    */
   virtual void 
-  activateKey(const Name& keyName);
+  activatePublicKey(const Name& keyName);
 
   /**
    * Deactivate a key. If a key is marked as inactive, its private part will not be used in packet signing.
    * @param keyName name of the key
    */
   virtual void 
-  deactivateKey(const Name& keyName);
+  deactivatePublicKey(const Name& keyName);
 
   /**
    * Check if the specified certificate already exists.
@@ -142,30 +142,6 @@
   virtual Name 
   getDefaultCertificateNameForKey(const Name& keyName);
 
-  /**
-   * Set the default identity.  If the identityName does not exist, then clear the default identity
-   * so that getDefaultIdentity() returns an empty name.
-   * @param identityName The default identity name.
-   */
-  virtual void 
-  setDefaultIdentity(const Name& identityName);
-
-  /**
-   * Set the default key name for the specified identity.
-   * @param keyName The key name.
-   * @param identityNameCheck (optional) The identity name to check the keyName.
-   */
-  virtual void 
-  setDefaultKeyNameForIdentity(const Name& keyName, const Name& identityNameCheck = Name());
-
-  /**
-   * Set the default key name for the specified identity.
-   * @param keyName The key name.
-   * @param certificateName The certificate name.
-   */
-  virtual void 
-  setDefaultCertificateNameForKey(const Name& keyName, const Name& certificateName);  
-
   virtual std::vector<Name>
   getAllIdentities(bool isDefault);
 
@@ -180,6 +156,32 @@
 
   virtual std::vector<Name>
   getAllCertificateNamesOfKey(const Name& keyName, bool isDefault);
+
+protected:
+  /**
+   * Set the default identity.  If the identityName does not exist, then clear the default identity
+   * so that getDefaultIdentity() returns an empty name.
+   * @param identityName The default identity name.
+   */
+  virtual void 
+  setDefaultIdentityInternal(const Name& identityName);
+
+  /**
+   * Set the default key name for the specified identity.
+   * @param keyName The key name.
+   * @param identityNameCheck (optional) The identity name to check the keyName.
+   */
+  virtual void 
+  setDefaultKeyNameForIdentityInternal(const Name& keyName);
+
+  /**
+   * Set the default key name for the specified identity.
+   * @param keyName The key name.
+   * @param certificateName The certificate name.
+   */
+  virtual void 
+  setDefaultCertificateNameForKeyInternal(const Name& certificateName);  
+
   
 private:
   class KeyRecord {
diff --git a/include/ndn-cpp/security/identity/basic-identity-storage.hpp b/include/ndn-cpp/security/identity/sec-public-info-sqlite3.hpp
similarity index 81%
rename from include/ndn-cpp/security/identity/basic-identity-storage.hpp
rename to include/ndn-cpp/security/identity/sec-public-info-sqlite3.hpp
index 0dc3e5d..335b724 100644
--- a/include/ndn-cpp/security/identity/basic-identity-storage.hpp
+++ b/include/ndn-cpp/security/identity/sec-public-info-sqlite3.hpp
@@ -6,8 +6,8 @@
  * See COPYING for copyright and distribution information.
  */
 
-#ifndef NDN_BASIC_IDENTITY_STORAGE_H
-#define NDN_BASIC_IDENTITY_STORAGE_H
+#ifndef NDN_SEC_PUBLIC_INFO_SQLITE3_HPP
+#define NDN_SEC_PUBLIC_INFO_SQLITE3_HPP
 
 // Only compile if ndn-cpp-config.h defines NDN_CPP_HAVE_SQLITE3.
 #include <ndn-cpp/ndn-cpp-config.h>
@@ -15,7 +15,7 @@
 
 #include <sqlite3.h>
 #include "../../common.hpp"
-#include "identity-storage.hpp"
+#include "sec-public-info.hpp"
 
 namespace ndn
 {
@@ -24,19 +24,19 @@
  * BasicIdentityStorage extends IdentityStorage to implement a basic storage of identity, public keys and certificates
  * using SQLite.
  */
-class BasicIdentityStorage : public IdentityStorage {
+class SecPublicInfoSqlite3 : public SecPublicInfo {
 public:
-  struct Error : public IdentityStorage::Error { Error(const std::string &what) : IdentityStorage::Error(what) {} };
+  struct Error : public SecPublicInfo::Error { Error(const std::string &what) : SecPublicInfo::Error(what) {} };
 
-  BasicIdentityStorage();
+  SecPublicInfoSqlite3();
   
   /**
    * The virtual Destructor.
    */
   virtual 
-  ~BasicIdentityStorage();
+  ~SecPublicInfoSqlite3();
 
-  // from IdentityStorage
+  // from SecPublicInfo
   /**
    * Check if the specified identity already exists.
    * @param identityName The identity name.
@@ -65,7 +65,7 @@
    * @return true if the key exists, otherwise false.
    */
   virtual bool 
-  doesKeyExist(const Name& keyName);
+  doesPublicKeyExist(const Name& keyName);
 
   /**
    * Add a public key to the identity storage.
@@ -74,7 +74,7 @@
    * @param publicKeyDer A blob of the public key DER to be added.
    */
   virtual void 
-  addKey(const Name& keyName, KeyType keyType, const PublicKey& publicKeyDer);
+  addPublicKey(const Name& keyName, KeyType keyType, const PublicKey& publicKeyDer);
 
   /**
    * Get the public key DER blob from the identity storage.
@@ -82,21 +82,21 @@
    * @return The DER Blob.  If not found, return a Blob with a null pointer.
    */
   virtual ptr_lib::shared_ptr<PublicKey>
-  getKey(const Name& keyName);
+  getPublicKey(const Name& keyName);
 
   /**
    * Activate a key.  If a key is marked as inactive, its private part will not be used in packet signing.
    * @param keyName name of the key
    */
-  virtual void 
-  activateKey(const Name& keyName);
+  virtual inline void 
+  activatePublicKey(const Name& keyName);
 
   /**
    * Deactivate a key. If a key is marked as inactive, its private part will not be used in packet signing.
    * @param keyName name of the key
    */
-  virtual void 
-  deactivateKey(const Name& keyName);
+  virtual inline void 
+  deactivatePublicKey(const Name& keyName);
 
   /**
    * Check if the specified certificate already exists.
@@ -110,7 +110,7 @@
    * Add a certificate in to the identity storage without checking if the identity and key exists.
    * @param certificate The certificate to be added.
    */
-  void
+  virtual void
   addAnyCertificate (const IdentityCertificate& certificate);
 
   /**
@@ -127,11 +127,11 @@
    * @return The requested certificate.  If not found, return a shared_ptr with a null pointer.
    */
   virtual ptr_lib::shared_ptr<IdentityCertificate> 
-  getCertificate(const Name &certificateName, bool allowAny = false);
+  getCertificate(const Name &certificateName, bool allowAny);
 
 
   /*****************************************
-   *           Get/Set Default             *
+   *            Default Getter             *
    *****************************************/
 
   /**
@@ -157,31 +157,6 @@
   virtual Name 
   getDefaultCertificateNameForKey(const Name& keyName);
 
-  /**
-   * Set the default identity.  If the identityName does not exist, then clear the default identity
-   * so that getDefaultIdentity() returns an empty name.
-   * @param identityName The default identity name.
-   */
-  virtual void 
-  setDefaultIdentity(const Name& identityName);
-
-  /**
-   * Set the default key name for the specified identity.
-   * @param keyName The key name.
-   * @param identityNameCheck (optional) The identity name to check the keyName.
-   */
-  virtual void 
-  setDefaultKeyNameForIdentity(const Name& keyName, const Name& identityNameCheck = Name());
-
-  /**
-   * Set the default key name for the specified identity.
-   * @param keyName The key name.
-   * @param certificateName The certificate name.
-   */
-  virtual void 
-  setDefaultCertificateNameForKey(const Name& keyName, const Name& certificateName);  
-
-
   virtual std::vector<Name>
   getAllIdentities(bool isDefault);
 
@@ -197,14 +172,50 @@
   virtual std::vector<Name>
   getAllCertificateNamesOfKey(const Name& keyName, bool isDefault);
   
-private:
+protected:
+  /**
+   * Set the default identity.  If the identityName does not exist, then clear the default identity
+   * so that getDefaultIdentity() returns an empty name.
+   * @param identityName The default identity name.
+   */
+  virtual void 
+  setDefaultIdentityInternal(const Name& identityName);
 
+  /**
+   * Set the default key name for the specified identity.
+   * @param keyName The key name.
+   * @param identityNameCheck (optional) The identity name to check the keyName.
+   */
   virtual void
+  setDefaultKeyNameForIdentityInternal(const Name& keyName);
+
+  /**
+   * Set the default key name for the specified identity.
+   * @param keyName The key name.
+   * @param certificateName The certificate name.
+   */
+  virtual void 
+  setDefaultCertificateNameForKeyInternal(const Name& certificateName);  
+  
+private:
+  void
   updateKeyStatus(const Name& keyName, bool isActive);
 
   sqlite3 *database_;
 };
 
+void
+SecPublicInfoSqlite3::activatePublicKey(const Name& keyName)
+{
+  updateKeyStatus(keyName, true);
+}
+
+void
+SecPublicInfoSqlite3::deactivatePublicKey(const Name& keyName)
+{
+  updateKeyStatus(keyName, false);
+}
+
 }
 
 #endif // NDN_CPP_HAVE_SQLITE3
diff --git a/include/ndn-cpp/security/identity/memory-private-key-storage.hpp b/include/ndn-cpp/security/identity/sec-tpm-memory.hpp
similarity index 88%
rename from include/ndn-cpp/security/identity/memory-private-key-storage.hpp
rename to include/ndn-cpp/security/identity/sec-tpm-memory.hpp
index ee4f706..5761597 100644
--- a/include/ndn-cpp/security/identity/memory-private-key-storage.hpp
+++ b/include/ndn-cpp/security/identity/sec-tpm-memory.hpp
@@ -5,11 +5,11 @@
  * See COPYING for copyright and distribution information.
  */
 
-#ifndef NDN_MEMORY_PRIVATE_KEY_STORAGE_HPP
-#define NDN_MEMORY_PRIVATE_KEY_STORAGE_HPP
+#ifndef NDN_SEC_TPM_MEMORY_HPP
+#define NDN_SEC_TPM_MEMORY_HPP
 
 #include <map>
-#include "private-key-storage.hpp"
+#include "sec-tpm.hpp"
 
 struct rsa_st;
 
@@ -19,15 +19,15 @@
  * MemoryPrivateKeyStorage extends PrivateKeyStorage to implement a simple in-memory private key store.  You should
  * initialize by calling setKeyPairForKeyName.
  */
-class MemoryPrivateKeyStorage : public PrivateKeyStorage {
+class SecTpmMemory : public SecTpm {
 public:
-  struct Error : public std::runtime_error { Error(const std::string &what) : std::runtime_error(what) {} };
+  struct Error : public SecTpm::Error { Error(const std::string &what) : SecTpm::Error(what) {} };
 
   /**
    * The virtual destructor
    */    
   virtual 
-  ~MemoryPrivateKeyStorage();
+  ~SecTpmMemory();
 
   /**
    * Set the public and private key for the keyName.
@@ -48,7 +48,7 @@
    * @param keySize The size of the key pair.
    */
   virtual void 
-  generateKeyPair(const Name& keyName, KeyType keyType, int keySize);
+  generateKeyPairInTpm(const Name& keyName, KeyType keyType, int keySize);
 
   /**
    * Get the public key
@@ -56,7 +56,7 @@
    * @return The public key.
    */
   virtual ptr_lib::shared_ptr<PublicKey> 
-  getPublicKey(const Name& keyName);
+  getPublicKeyFromTpm(const Name& keyName);
   
   /**
    * Fetch the private key for keyName and sign the data, returning a signature Blob.
@@ -101,7 +101,7 @@
    * @param keySize The size of the key.
    */
   virtual void 
-  generateKey(const Name& keyName, KeyType keyType, int keySize);
+  generateSymmetricKey(const Name& keyName, KeyType keyType, int keySize);
 
   /**
    * Check if a particular key exists.
diff --git a/include/ndn-cpp/security/identity/osx-private-key-storage.hpp b/include/ndn-cpp/security/identity/sec-tpm-osx.hpp
similarity index 77%
rename from include/ndn-cpp/security/identity/osx-private-key-storage.hpp
rename to include/ndn-cpp/security/identity/sec-tpm-osx.hpp
index 6ac28ea..0b90fd0 100644
--- a/include/ndn-cpp/security/identity/osx-private-key-storage.hpp
+++ b/include/ndn-cpp/security/identity/sec-tpm-osx.hpp
@@ -5,48 +5,48 @@
  * See COPYING for copyright and distribution information.
  */
 
-#ifndef NDN_OSX_PRIVATEKEY_STORAGE_H
-#define NDN_OSX_PRIVATEKEY_STORAGE_H
+#ifndef NDN_SEC_TPM_OSX_HPP
+#define NDN_SEC_TPM_OSX_HPP
 
 // Only compile if ndn-cpp-config.h defines NDN_CPP_HAVE_OSX_SECURITY 1.
 #include <ndn-cpp/ndn-cpp-config.h>
 #if NDN_CPP_HAVE_OSX_SECURITY
 
 #include "../../common.hpp"
-#include "private-key-storage.hpp"
+#include "sec-tpm.hpp"
 
 namespace ndn
 {
   
-class OSXPrivateKeyStorage : public PrivateKeyStorage {
+class SecTpmOsx : public SecTpm {
 public:
+  struct Error : public SecTpm::Error { Error(const std::string &what) : SecTpm::Error(what) {} };
+
   /**
-   * constructor of OSXPrivateKeyStorage
+   * constructor of OSXKeyChainTpm
    * @param keychainName the name of keychain
    */
-  OSXPrivateKeyStorage(const std::string & keychainName = "");
+  SecTpmOsx(const std::string & keychainName = "");
 
   /**
-   * destructor of OSXPrivateKeyStore
+   * destructor of OSXKeyChainTpm
    */    
   virtual 
-  ~OSXPrivateKeyStorage();
+  ~SecTpmOsx();
 
 
-  // From PrivateKeyStorage
+  // From TrustedPlatformModule
   virtual void 
-  generateKeyPair(const Name& keyName, KeyType keyType = KEY_TYPE_RSA, int keySize = 2048);
+  generateKeyPairInTpm(const Name& keyName, KeyType keyType = KEY_TYPE_RSA, int keySize = 2048);
 
   virtual ptr_lib::shared_ptr<PublicKey> 
-  getPublicKey(const Name& keyName);
+  getPublicKeyFromTpm(const Name& keyName);
   
   virtual Block
-  sign(const uint8_t *data, size_t dataLength,
-       const Name& keyName, DigestAlgorithm digestAlgorithm = DIGEST_ALGORITHM_SHA256);
+  sign(const uint8_t *data, size_t dataLength, const Name& keyName, DigestAlgorithm digestAlgorithm);
 
   virtual void
-  sign(Data &data,
-       const Name& keyName, DigestAlgorithm digestAlgorithm = DIGEST_ALGORITHM_SHA256);
+  sign(Data &data, const Name& keyName, DigestAlgorithm digestAlgorithm);
   
   /**
    * Decrypt data.
@@ -57,7 +57,7 @@
    * @return The decrypted data.
    */
   virtual ConstBufferPtr 
-  decrypt(const Name& keyName, const uint8_t* data, size_t dataLength, bool isSymmetric = false);
+  decrypt(const Name& keyName, const uint8_t* data, size_t dataLength, bool isSymmetric);
 
   /**
    * Encrypt data.
@@ -68,7 +68,7 @@
    * @return The encrypted data.
    */
   virtual ConstBufferPtr
-  encrypt(const Name& keyName, const uint8_t* data, size_t dataLength, bool isSymmetric = false);
+  encrypt(const Name& keyName, const uint8_t* data, size_t dataLength, bool isSymmetric);
 
   /**
    * Generate a symmetric key.
@@ -77,7 +77,7 @@
    * @param keySize The size of the key.
    */
   virtual void 
-  generateKey(const Name& keyName, KeyType keyType = KEY_TYPE_AES, int keySize = 256);
+  generateSymmetricKey(const Name& keyName, KeyType keyType, int keySize);
 
   /**
    * Check if a particular key exists.