Disclosed is a self-contained hardware-based authentication system that incorporates different authentication protocols for access to soft and/or hard assets with different security levels. The system embodiments include the use of a RFID device that comprises dual RFID tags operating under different frequencies. Specifically, one RFID tag operates on a public frequency and, when activated, transmits an identifier encrypted using a public key. The other RFID tag operates on a private frequency and, when activated, transmits a private key that can be used to decrypt the encrypted identifier. Upon receipt by a processor (e.g., a local processor or security server) of a request for access to a specific asset, a security level for the specific asset is determined. Then, depending upon the particular security level (e.g., low, medium or high) different authentication protocols are instituted using the RFID device. Also disclosed are embodiments of an associated authentication methodology.