GBDE, or Geom-Based Disk Encryption, has specific features for high-security environments where protecting the user is just as important as concealing the data. In addition to a cryptographic key provided by the user, GBDE uses keys stored in particular sectors on the hard drive. If either key is unavailable, the partition can’t be decrypted. Why is this important? If a secure data center (say, in an embassy) comes under attack, the operator might have a moment or two to destroy the keys on the hard drive and render the data unrecoverable. If the bad guys have a gun to my head and tell me to “enter the passphrase or else,” I want the disk system to say, The passphrase is correct, but the keys have been destroyed. I don’t want a generic error saying, Cannot decrypt disk. In the first situation, I still have value as a blubbering hostage; in the latter, either I’m dead or the attackers get unpleasantly creative.
Absolute FreeBSD, 3rd Edition, Michael W. Lucas (2018), chapter 23
Absolute FreeBSD, 3rd Edition, Michael W. Lucas (2018), chapter 23