truecrypt

TrueCrypt is a software system for establishing and maintaining an on-the-fly-encrypted 
volume (data storage device).

To create a file-base encrypted volume

$ truecrypt -t -c

To use on Jolla you need to supply truecrypt with the "-m=nokernelcrypto" parameter

For example encrypted file created is named encrypted.tc and is to be mounted in /home/nemo/mount folder:

$ mkdir ~/mount
$ truecrypt -m=nokernelcrypto -t ~/encrypted.tc ~/mount