From Wonderful Disk:
Wonderful Disk is a handy "on-the-fly" transparent disk encryption application. Using this software, you can create one or more "virtual encrypted disk" on your PC. These disks operate exactly like a normal disk, with the exception that anything written to one of them is transparently, and securely, encrypted (AES encryption) before being stored on your computer's hard drive.
Here are some key features:
Security : The data on the disk is transparent encryption and decryption.
Usability : Simply create an encrypted file, no formatting.
Specificity : Compared to similar products, Wonderful Disk do not pre-allocate space, only allocate space when needed, so minimize the disk space occupied by.