Drag'n'Crypt ULTRA!

[TrueCrypt is not exactly "Open Source", but the source is available. See the reviews to get more information.]

GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications. A wealth of frontend applications and libraries are available. Version 2 of GnuPG also provides support for S/MIME.

AxCrypt is a simple file encryption software for Windows. It integrates seamlessly with your workflow to encrypt, decrypt, store, send and work with files.

AES Crypt is an advanced file encryption utility that integrates with the Windows shell or runs from the Linux command prompt to provide a simple, yet powerful, tool for encrypting files using the Advanced Encryption Standard (AES). A Java library is also available for developers using Java to read and write AES formatted files.

Easy File Locker is a pretty small file at 224KB and will do exactly what it says. It will let you protect a file or folder from being seen or accessed by anyone on your system. This is a light-weight program that does not slow down your system and even continues working if the machine is booted in safe mode. It does not require the application to be running for the security to work and it can be password-protected as well.

LibreCrypt (formerly DoxBox) is an open-source disk encryption for Windows and the successor of FreeOTFE

GPG for Mailis an open source plugin for Apple Mail. Encrypt, decrypt, sign and verify mails using OpenPGP with a few simple clicks.

If your computer were ever to be stolen, are you certain that your personal information cannot be discovered? Jetico’s BestCrypt software automatically encrypts your files so that nobody can read the data unless they have the right password or keys.

DCrypt is an encryption and decryption tool that combines in a smart way multiple algorithms. The combination of multiple strong algorithms makes it much more difficult for hackers to get the plain content of the encrypted file without the password.

LUKSUS is a tool that creates an encrypted volume and filesystem on a hardrive or other storage media as well as a filecontainer.It can use the following encryption facilities: LUKS, Truecrypt and GELI.

Free Hide Folder is a free computer security software to hide your private folders. It is very useful to keep your personal data away from others. Others will not know where your personal files exist and they will not be able to accidentally view them. You can hide folders simply with a few mouse clicks. Free Hide Folder is protected by a password that you can change or remove at any time. Why do you need Free Hide Folder?

ProxyCrypt is a command line tool that creates encrypted volumes within a file or a hard drive.It works as a "proxy" for the ImDisk Virtual Disk Driver .

Securely encrypt your private and confidential files or whole folders.The encryption/decryption process is simply done by dragging the selected file(s) or folders(s) to application window.Files are encrypted using strong encryption algorithm: AES (Rijndael) 256bit, RC6 256bit, Serpent 256bit, Blowfish 448bit, Twofish 256bit, GOST 256bit + (Threefish 1024bit and SHACAL-2 512bit for Pro Version) ciphers are available.Cross-Platform (Windows, Linux, Mac OS X, ...) GUI Version and Command Line Version are available.Compatible with the Secret Space Encryptor for Android.A wide range of compatible platforms (desktop and mobile) allow easy sharing of protected data.Easy to use. »