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 users to backup and restore the critical areas of volume files.
- Keyfile support included; store volumes and their associated metadata separately.
- Uses per-sector IVs, including support for ESSIV.
- Volume file timestamps and attributes are reset after dismounting, increasing "plausible deniability".
- Supports volumes files up to 2^63 bytes (8388608 TB).
- Plus more...!