While the best security (and speed) often comes from hardware-secured flash drives with their built-in cryptologic co-processors, anyone can secure their regular flash drive through the use of a free open source program called TrueCrypt. TrueCrypt offers a large array of encryption algorithms to choose from including 256-bit AES, Serpent and TwoFish, or any combination of all three, and is available for Windows, Mac and Linux operating systems.