9.12. Encrypt Partitions
If you selected the Encrypt my data option, when you click to proceed to the next screen the installer will prompt you for a passphrase with which to encrypt the partitions on the system.
Choose a passphrase and type it into each of the two fields in the dialog box. If the passphrase is not strong enough, a warning symbol will appear and you will not be allowed to type in the second field. You must provide this passphrase every time that the system boots.
If you lose this passphrase, any encrypted partitions and the data on them will become completely inaccessible. There is no way to recover a lost passphrase.