ECryptfs

eCryptfs is Article description::an in-kernel file encryption suite.

Emerge
Install :

/etc/pam.d
See the below diff for the file.

Encrypting your SWAP
Ecryptfs-utils has a utitlity which depends on. However, this utility is currently Ubuntu centric. You should setup an encrypted swap by installing and edit   which has an example of an ecrypted swap in it.

Also note, you need to add dm-crypt to the boot run level with:

You can find a version of which works with gentoo.

External resources

 * eCryptfs on the Arch wiki