Your data can be securely encrypted using the recognized AES method. This permits O&O DiskImage to provide your image with an extremely high level of security with a key length of up to 256 bits.
You can select the encryption level for your files under Drive operation/Imaging options/Image file/Security. If you then start the imaging process (Drive imagings), enter a password when being prompted.
A belated encryption of the image is possible under Convert image file.