FreeOTFE is a free, open source, "on-the-fly" (OTFE) transparent disk encryption program.  
 
Using this software, you can create one or more "virtual disks" on your PC - anything written to which will be automatically, and securely, encrypted before being stored.  
 
Features include:  
 
- Source code freely available.  
- Easy to use; full wizard included for creating new volumes.  
- Data encrypted on your PC can be read/written on your PDA, and vice versa.  
- Powerful: Supports numerous hash/encryption algorithms, and provides a greater level of flexibility than a number of other (including commercial!) OTFE systems.  
- Hash algorithms include: MD5, SHA-512, RIPEMD-160, Tiger and many more.  
- Cyphers include AES (256 bit), Twofish (256 bit), Blowfish (448 bit), Serpent (256 bit) and many more.  
- "Portable mode" included; FreeOTFE doesn't need to be installed before it can be used - making it ideal for carrying your data securely on USB drives!  
- Operates under both PC (MS Windows 2000/XP) and PDA (Windows Mobile 2003/2005) platforms.  
- Linux compatibility (Cryptoloop "losetup", dm-crypt and LUKS supported).  
- "Hidden" volumes may be concealed within other FreeOTFE volumes, providing "plausible deniability".  
- FreeOTFE volumes have no "signature" to allow them to be identified as such.  
- Encrypted volumes can be either file or partition based.  
- Modular design allowing 3rd party drivers to be created, incorporating new hash/cypher algorithms.  
- Supports password salting (up to 512 bits), reducing the risks presented by dictionary attacks.  
- Allows