Hi, this is my first post, so hopefully this makes some sense.
A great encryption program is truecrypt. Available at
http://www.truecrypt.org it is open source, it is free and runs on window and linux. Here are some of it's features.
Main Features:
* Creates a virtual encrypted disk within a file and mounts it as a real disk.
* Encrypts an entire hard disk partition or a device, such as USB flash drive.
* 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)
2) No TrueCrypt volume can be identified (volumes cannot be distinguished from random data).
* Encryption algorithms: AES-256, Blowfish (448-bit key), CAST5, Serpent, Triple DES, and Twofish.
Mode of operation: LRW (CBC supported as legacy).
* Based on Encryption for the Masses (E4M) 2.02a, conceived in 1997.
On my usb drive I created a standard volume within a file that uses about half of the drive, this leaves room for emergency contact information/medical information that I would want someone to see if I were in an accident. It can be run directly from the usb drive and does not leave behind any traces on the PC. As long as you have a strong pass phrase, decrypting the volume would be very difficult if not impossible.
I also use another open source piece of software called keypass, a password manager available at
http://keepass.sourceforge.net . I use this to store all of my passwords, It can also be run directly of of the USB drive without anything being written to on the client PC. It is also highly encrypted and is as secure as your pass phrase.
If you want to be extremely secure/paranoid with your pass phrases. You can get cryptographic-strength random password strings from
http://www.grc.com/password. Just copy the number of characters you need/want your passord to be (the longer the better) and save them in keepass. I use full 63 character "passwords" for my more secure files. It can be a hastle, but security always is.
Mostly I just want to make sure that if someone were to find/take my usb drive they will have one of two options. Contact me with the emergency contact intormation on the drive and return it, or realize that there is nothing "good" on it for them and reformat it to use as their own.
There are also some other great open source programs out there like portable openoffice and portable firefox.
If I was unclear about anything, let me know.