How does PGP Whole Disk Encryption work?

Question

I have PGP Whole Disk Encryption running on my desktop at work. When I turn on the computer I get a grey screen like this one asking for my password. I type in my Windows password and move right along.

When I change my Windows password, the PGP Whole Disk Encryption password changes, too! How did it do that?! If the disk is being re-encrypted with the new password, I'd expect it to take a long time to rewrite the whole disk. Or is the disk not really encrypted? What's going on?

Answer 1

When I change my Windows password, the PGP Whole Disk Encryption password changes, too! How did it do that?! If the disk is being re-encrypted with the new password, I'd expect it to take a long time to rewrite the whole disk. Or is the disk not really encrypted? What's going on?

When using PGP WDE, the password you type is really just a "proxy" to unlock a longer, randomly generation encryption key that is actually used to encrypt the data on disk. Changing your password only requires updating the encrypted key on disk.

Answer 2

As Iarsks said the PGP password is just a mean to access the encryption key. It is similar to the Windows account password that provides access to the user's private encryption key used to protect "private encrypted folders". If you change the account password, you don't re-encrypt the folders (you don't change the key).