Authentication is a process that compares credentials that must match. Authentication is performed by a protected pre-boot OS on the SSD. Pre-boot Authentication (PBA) guarantees that there is no way to start breaking into the SSD. PBA supports multiple factor authentication: biometrics, smart cards, or remote passwords. TCG created specifications called the Opal SSC (Security Subsystem Class). This standardized the security features of SEDs. Two subsets under Opal are Opalite and Pyrite, a non-encrypting version of Opalite. More information about Opal can be found at TrustedComputingGroup.org. SEDs can support either TCG Opal 2.0 or ATA Security based authentication. The host system and its BIOS will determine which authentication method is used.