security: MemoryIdentityStorage: Implemented addIdentity, setDefaultIdentity.
diff --git a/ndn-cpp/security/identity/identity-storage.hpp b/ndn-cpp/security/identity/identity-storage.hpp
index 52ec3b4..daead73 100644
--- a/ndn-cpp/security/identity/identity-storage.hpp
+++ b/ndn-cpp/security/identity/identity-storage.hpp
@@ -137,7 +137,7 @@
/**
* Get the default identity.
- * @param return The name of default identity.
+ * @param return The name of default identity, or an empty name if there is no default.
*/
virtual Name
getDefaultIdentity() = 0;
@@ -170,7 +170,8 @@
getDefaultCertificateNameForKey(const Name& keyName) = 0;
/**
- * Set the default identity.
+ * 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