What does the rearranging numbers scene mean?

As for the the rearranging numbers thing, that barely makes any sense but he wore those lenses in order to scan the real code into the suitcase they gave the bad guy. At first, they thaught they would be able to give the bad guy any random number but when they discovered he brought another dude that can tell if it's the right code or not, they had to change plans. So lots of non-sense and contradictions if you aske me. Otherwise, you, me and everyone that failed to answer for the past 7 months are all too dumb to see the logic in this.

As the meetings were taking place simultaneously, they had to provide codes from the briefcase that were legit, without knowing what they were. The idea was that in the trade for the diamonds, Brandt wore glasses and would 'confirm' the codes, while the glasses scanned the codes and sent that data wirelessly to the briefcase, which would then print the codes.

I can't remember how jumbling the numbers would work and still provide legitimate codes, but they eventually had to scrap that part of the plan anyway.