Try truecrypt, it creates an encrypted HARD DISK in your computer that will require a password to open and view the files inside, u can also encrypt an already exisiting hard disk. Truecrypt allows you to use a normal file as a crypt file. That means u can select an Mp3 or text file and use it to store files inside and it will still appear as an mp3 or text file in the computer. U can also carry the encrypted file to any computer and open it if there is truecrypt installed.
Main Features:
Creates a virtual encrypted disk within a file and mounts it as a real disk.
Encrypts an entire partition or storage device such as USB flash drive or hard drive.
Encrypts a partition or drive where Windows is installed (pre-boot authentication).
Encryption is automatic, real-time (on-the-fly) and transparent.
Provides two levels of plausible deniability, in case an adversary forces you to reveal the password:
1) Hidden volume (steganography) and hidden operating system.
2) No TrueCrypt volume can be identified (volumes cannot be distinguished from random data).
Encryption algorithms: AES-256, Serpent, and Twofish. Mode of operation: XTS.
Further information regarding features of the software may be found in the documentation.
download for windows, mac or linux
URL:
http://www.truecrypt.org/downloads
