Solid Encryption 1.21
This gives you access to unbreakable OTP encryption. You can encrypt to and from files or directly to the clipboard. Paste cipher-text directly into text documents. Generate real random keys with no more than a radio and a sound card. One-Time Pad (OTP) encryption a.k.a. infinite key encryption. OTP encryption is absolutely unbreakable if used correctly. This system is well known and has been used for a long time by various intelligence agencies

CHAOS Universal 6.2
CHAOS Universal hides secret information in sound, image, and text files (BMP, WAV, TXT, HTML). This sensitive data is being encrypted beforehand. That way files can be sent over the Internet without being discovered by a third party.

Masker 7.0.8
Masker is a program that encrypts your files so that a password is needed to open them, and then it hides files and folders inside of carrier files, such as image files, video, program or sound files. You can hide any files and even whole folders. The strong encryption up to 448-bit and password protection makes the hidden data inaccessible for unauthorized users! Use Masker to keep you sensitive secret files secure hidden and super-protected!

Folder Security 2.6 2.6
Folder Security is a software program designed to password-protect folders. It lets you prevent people from viewing, printing, or altering your confidential documents. Folders remain protected should your PC be rebooted into Windows Safe Mode or DOS. A nice feature is the ability to include a password hint. Choose something sensible and it will prompt you to remember your password, without giving it away to anybody else.

Steganography 1.8.1.1115
Steganography enables you to use digital data hiding techniques (steganography) to hide files and messages within other files (carriers) such as picture or sound files. This allows you to encrypt sensitive information, while at the same time hiding it in a file that will not look suspicious, so nobody even knows that there is any encrypted information.