Disclosed are embodiments of a radio frequency identification (RFID) authentication system and an associated authentication methodology. The embodiments incorporate an identification device (e.g., an identification badge, a key fob, etc.) with an embedded RFID tag. The embedded RFID tag is associated with a specific user and stores a private key generated as part of a public key-private key encryption scheme. The private key is read by an RFID reader and used to decode public key encrypted data stored within or accessible by a computer system (e.g., a desktop computer system, a laptop computer system, a personal digital assistant (PDA), a digital fax machine, wireless telephone, etc.). Thus, the embodiments provide a portable way to use public key-private key encryption scheme data anywhere using RFID technology.