The data verification kit DVK-E1, concurrently developed with the EOS-1Ds, works on the computer to determine the correct code for the image and compare it with a code attached to the image. DVK-E1 consists of a dedicated IC card and card reader, together with special software for Windows 2000/XP. This allows one to check that the EOS-1Ds' image files have remained absolutely unaltered after being circulated. This may well be a landmark for digital imaging in law enforcement, copyright and many other areas.