TrueCrypt

At this time the program is open source reference for encryption and protection of personal data. Allows you to encrypt files, folders and entire partitions with the most famous 256-bit encryption algorithms (AES, Twofish, Serpent), also using 2 of these algorithms simultaneously. The program is able to create a hidden encrypted volume within another encrypted volume, so as to leave a safe area invisible even if we are forced to reveal the password (this feature is only for experienced users, since Because if you are able you may lose all data in the hidden volume).

The volume to be encrypted may want to have any extension (.txt, .rar, .zip, .iso, .Mp3, .jpg, etc.., Or any extension): TrueCrypt-only and with the right password, will be able to open it. Nor is it possible to establish that we have encrypted the file has been encrypted with TreuCrypt (this is a further step towards the confidentiality).

Truecrypt does not need to install: you can run from any device to open and use-for example-some encrypted volume within the disk drive.
For the avoidance of doubt, remember that encrypt a partition can have devastating effects if you do not understand what you do, before combining irreparable damage, it should think very carefully before acting.

TrueCrypt