I had a government customer once ask me about whole drive encryption. This was before the advent of such devices as Seagate’s DriveTrust drives. At the time, the only viable solution for whole drive encryption was PGP Disk.
But before we can start talking about solutions, it might be better to give a clearer understanding of how data is encrypted.
What is AES?
AES is an abbreviation of Advanced Encryption Standard. It is a standard developed by the public and accepted by the government for encrypting data. AES uses the Rijndael encryption cipher and can be used with varying key lengths of 128, 192 and 256 bits. The most common and most secure is 256 which has been approved for protecting even Top Secret data by the NSA. Because of the multiple key lengths, you will commonly see it referred to as AES-128, AES-192 and AES-256 respectively.
The technical details on how encryption works can get quite cumbersome. For an overview of the standard, how it was developed and how it works, you may wish to read the Wikipedia entry here . For a deeper understanding of cryptography, the best book by far that I have read on the subject is Applied Cryptography by Bruce Schneier of CounterPane. Another excellent book that Bruce makes reference to is “The Code Breakers: The Comprehensive History of Secret Communication from Ancient Times to the Internet .” While the first deals with the details and mathematics behind encryption, the latter provides a page turning tome of intrigue.