TrueCrypt

This is one of the most famous data encryption programs, built on the idea that a truly secure encryption program should have open source code. TrueCrypt is free and distributed with its source code under the TrueCrypt License.

It supports AES, Serpent and Twofish encryption algorithms, as well as cascades of them, and the RIPEMD-160, SHA-512 and Whirlpool hash functions for key creation. The data is encrypted on the fly, and placed in a special container that can be connected as a virtual drive, as well as copied or transferred to other media. It is also possible to encrypt partitions on hard drives or USB sticks, the Windows system partition, and to create hidden volumes.

Unfortunately, in 2014, development of the program was discontinued under rather strange circumstances; the official page now warns that TrueCrypt is not secure. Despite this, version 7.1a still works, but it is better to use it only for familiarization purposes or to open old volumes. For reliable data protection it is recommended to use VeraCrypt - a separate branch from TrueCrypt, which supports more algorithms and continues to be actively developed.

The main benefit of using TrueCrypt is that it provides on-the-fly, robust data encryption for files, hard drives and USB sticks.