If you're a Mac user concerned with security, Apple has added a new feature to the Mountain Lion operating system to make it more convenient for users to encrypt secondary volumes on a Mac computer. Users can access the new encryption menu options inside Mountain Lion by right clicking on a non-boot volume in Finder. The menu that pops up now has an option for encrypting the disk.
When the user selects the encryption option, a window will open asking the user to enter a password and password hint for the drive. Once those are entered, the volume will start the encryption process. Exactly how long it takes to encrypt the volume will naturally depend on the number of files on the drive volume.
Once the encryption process is finished, Mountain Lion will unmount and mount the volume as an encrypted storage location. It's important note that it has been possible to encrypt secondary hard drives before Mountain Lion, but the new menu feature baked into the OS makes the encryption process much easier. With the new feature, no special steps have to be performed using other software or DiscUtility.
Another interesting note, users who wish to encrypt their boot volume can do so using Mountain Lion from the FileVault section inside the Security & Privacy system preference area. One potential downside to using disk encryption in Mountain Lion is that the drive will only be readable on Mac computers that support the required CoreStorage- Lion and Mountain Lion.