Full Disk Encryption software?

[opendoors]

Is there open source software (similar to TrueCrypt) for Ubuntu that allows me to encrypt the entire hard drive? I don't want to use TrueCrypt unless there really are no other options because of its license and because they are so picky about which emails are allowed to register for their forum.

I need something that can also allow me to encrypt removable devices such as external hard drives and flash drives. Any help would be appreciated!

[jeremyjjbrown]

I believe true crypt does. Crypt Keeper is also another utility for managing encryption but I believe it is only for directories.

[FuturePilot]

LUKS. You can do it with Disk Utility under the System > Administration menu.