BitLocker, formerly known as "Secure Startup", this feature offers full disk encryption for the system volume. Using the command-line utility, it is possible to encrypt additional volumes. Bitlocker utilizes a USB key or Trusted Platform Module (TPM) version 1.2 of the TCG specifications to store its encryption key. It ensures that the computer running Windows Vista starts in a known-good state, and it also protects data from unauthorized access. Data on the volume is encrypted with a Full Volume Encryption Key (FVEK), which is further encrypted with a Volume Master Key (VMK) and stored on the disk itself.