KeePass - KeePass is an open source password manager. Passwords can be stored in highly-encrypted databases, which can be unlocked with one master password or key file.

Knox - Knox offers easy disk image encryption and comes with a built-in backup service.

Passbook - Password manager for GNOME desktop, Gnome Keyring Manager and Viewer

R-Crypto - R-Crypto is smart data security and disk encryption software that allows you to secure your sensitive information via strong encryption.

Seahorse - Front end for GnuPG.

Exocet - Exocet creates a Folder on your System.