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UPDATED : Flaw found in the software of Xerox scanners

the numbers in your copy may not always be correct


Update : Xerox have been in touch with ourselves regarding the issue. They have made a blog post which you can read here, it details two fixes for the issue, the post also mentions that Xerox believe the issue to be caused by users changing the default scan settings, to improve file sizes, rather than it being an out of box problem.

The two solutions are below :

"Reset Scanning Defaults:  Xerox is providing a guide demonstrating how to check the current device scan settings and how to return them to factory default.
Apply a Software Patch:  Xerox is developing a software patch that can be remotely downloaded to each device.  The software patch will disable the highest compression mode thus completely eliminating the possibility for character substitution.  Xerox will begin rolling out the patch within a few weeks".


A potentially serious error in Xerox scanners and copiers has surfaced today. The flaw meant that numbers in scanned documents were randomly changed without the users knowledge, from the source material.

In a blog post, a computer scientist discovered and posted the results of the error from various Xerox scanners. Using real life copies to show the changes. The information to be copied are from a building floor plan which shows the total area of each room.  When scanned you can see that on certain runs, the numbers varied massively.


Vast differences on certain copiesVast differences on certain copies


The error, seems to have been caused by the way the software compresses the copies. The devices use a compression standard called JBIG2, which tries to make each copy as small as possible, in doing so the software will re-use "simalar" areas on the page rather than the original data that is on the page. The standard does have a margin for error, which as long as it is not too high is the reason this occurs. This is why certain times the number 6 is changed into an 8 for example.  

The JBIG2 compression standard is quite common, which makes me think that the flaw could be present in other copiers or scanners that also use this method to compress copies at low quality settings.


Thankfully Xerox have been in touch with the blogger over the error and have already suggested a viable workaround  which switches off the JBIG2 compression. The workaround is simply to increase the copying quality on the device, although the blogger reports that this actually reduced the overall readability of some scans.