DriveCrypt

In the author's words, "You create an encrypted file (or several) that pretends to be another disk (hard or removable) and stores data. The data is protected with up to 1344b tripple blowfish cipher and 256b hash key. Up to 4 arbitrary passwords can be used for access, and they have to come in the right place, so even if someone knows the passwords, they still have to know their position. It is possible to create any number of "access passwords" and even specify their flatness (days, time, rights) and thus only share data when allowed. It is also possible to extend the security with a mechanical key (called a token), so that in addition to knowing the password, a mechanical element in the USB port is also needed (this can also be used to store a digital signature and other security information). The application allows the creation of an "unlimited" number of virtual disks, both on HDD and on DVD,CD,FDD,USB,memory cards... .
This ensures perfect data protection even if the backup media is stolen and the owner does not have to worry about misuse of data, he loses only the medium itself."