TrueCrypt is an app that creates a virtual volume which is encrypted, and it allows user to keep private information safe. TrueCrypt for Ubuntu comes with the tray icon which displays on the panel. Installing the TrueCrypt isn't necessary on the system you can download from official site and use it as portable application but it is better to install under Linux if your system drives are encrypted with it.
It is user friendly program and very easy to use, just need little bit knowledge about file-systems and volumes. It offers two options to create encrypted standalone file which can contain many files depend on the size of encrypted file set by user, other option is to encrypt non-system drive so all data under this drive will be encrypted (Beware it will completely destroy your data if you have something on your drive).
For strong encryption use AES encryption with SHA-512 Hash algorithm and choose password which contains numbers, symbols, upper/lower case letters and should be 20+ character long.
Features of Truecrypt:
- Entire partition encryption such as USB flash drive or HDD.
- Virtual disk within a file and stores files in it like a read disk.
- Encryption is automatic, real-time (on-the-fly) and transparent.
- Parallelization and pipelining allow data to be read and written fast, as if the drive was not encrypted.
- Provides plausible deniability, in case an adversary forces you to reveal the password.
- Encryption algorithms: AES-256, Serpent, and Twofish.
(These screenshots are not tutorial)
Warning: If you are beginner and don't know how to use it, just follow this official tutorial or search videos on YouTube. Otherwise you will lose your data.