As I promised in the post about a data encryption utility called TrueCrypt, I am going to show you another utility that can be used to encrypt portable data on a USB drive. Unlike TrueCrypt, in which you must have administrative rights to activate the program for accessing the encrypted data, this program allows you to operate it on a public computer on which you do not have administrative rights.

To get this free program, go to this link:

Similar to TrueCrypt, you must create a container file to store your encrypted files. Therefore, first use a computer that you do have administrative rights on, get the installation file, and install it on that computer.

Follow the program’s instructions to create a container file. After the file creation, you will find a system folder (_rohos) in your USB thumb drive with the container file named “rdisk.rdi” as shown below:

Please note this free version allows you to create a virtual container file with maximum volume of 1 GB.

Now map this Rohos mini drive as drive “R” in your system (“R” is the default drive letter that you can change) and load it with the data files you want to securely store. (Just copy and paste those files to the drive file by ordinary file copy process.)

Next try the Rohos drive in a computer for which you do not have administrative rights. (You can also simply log into the same computer with a limited privileges account.) You can now double click the “Rohos mini.exe” file (shown as yellow icon above) in your USB thumb drive and the program will ask you to input the password to access your container file under “_rohos” folder.

Supply the correct password used previously for the container file. Rohos will return with a browser window containing all your encrypted files.

You can double click any file to open it in its associated program. Rohos will temporarily decrypt the file and load it into the temp directory it creates on your USB memory device in order for the system application to access it.

You can save any file within the Rohos Disk Browser to the local computer by accessing the FileSave function. The software will prompt you to enter the designated folder location to store the decrypted file.

To copy any file from your local computer to this container file (and encrypt it at the same time), just drag and drop any file from any file directory to the Disk Browser Window.

To shut down the program, simply close the Browser Window. The software will prompt for confirmation to clean up any decrypted files in the temporary directory.

The beauty of this program is you can use it anywhere on any computer, even if you do not have administrative rights. It also offers both AES 256 bit and Blowfish encryption technology to protect the data. Both are world-class encryption technologies that we can depend on.

However, please note the following limitations of the program:

  • You can only create a container file with a maximum capacity of 1GB for the free version. Also, you can only create one container file per USB thumb drive’s partition.
  • Nothing is known about the random number generator the program uses to create the encryption key. Is there any weakness in the random number generator it is using? Unlike TrueCrypt, it does not ask for the user’s input to help create the random number to generate the encryption key.
  • The program is not developed under Open-Sourced effort. Therefore, the code is proprietary and closed. Nothing is known about any possible inherent weakness in the program design because it has not been reviewed publicly by security and programming experts.

This software provider does provide a paid version with enhanced features such as storage size exceeding 1GB, allowing more than one encrypted virtual drives on single USB drive, and more.

If you have any comments and ideas about using the Rohos Mini Drive, leave me a message here.

Tags: Blow Fish, USB Data Encryption