Hi again.lmviterbo wrote: ↑Thu Jun 18, 2020 1:57 am I'm thinking of one immediate advantage in the "Cxxxx4567xxx" layout: anyone browsing the banknotes recently registered by a specific EBTor can, wih that layout, spot a faker when you see a hit in a series. This (hit in series) is one of the most common reports in the "Discussions about investigations" topic under the hidden Database subforum (accessible only to members of the Database Working Group).
Maybe there's other advantages I don't know of.
I haven't gone into detailed analysis, but I know that layouts like "C012xxxxx89x" allow, in various combinations value/printer_letter/serial_letter, makes it possible or someone in the know to derive the plate (like "C001xx") and/or the cell (like "CxxxA1").
Sorry I have taken so long to reply.
I do not agree on what you write about fake serial hits. As far as I can imagine, opportunity of faking hits exists same way if you have Cxxxx4567xxx as if you have CT12xxxxx89x. A total of 6 digits, one of which checksum, are hidden in both cases.
Also, in my post, I wrote that a skilled user could figure out if one of the hidden digits could be CT12x4xxx89x given printing plate C023 if published. Well: my mistake, this is not true. This middle 4 could be figured out if the printing grid was published, or at least one position, let's say C023Dx or C023x4, but not just for the printing plate number, since plate number 023 actually prints ALL the serial numbers from, for example CS47xxxxxxxx to CT69xxxxxxxx.
And, given the C, you have the checksum, but:
1st: even showing only Cxxxxxxxxxxx, you ALSO give the checksum value, and
2nd: still need to guess a further 5 digits that can literally go from 00000 to 99999, so one out of 10,000 possibilities.