What is the purpose of the 6th digit?
It doesnt add any security, as it is trivially computable from the other digits already computed.
It appears to be a checksum, but I can't see why one would be needed.
It doesnt add any security, as it is trivially computable from the other digits already computed.
It appears to be a checksum, but I can't see why one would be needed.
This is an early POC, and sanity checks like this are exactly the kind of feedback I’m looking for.
The computation of the code is not computationally expensive (human computation is a requirement) so no real impact on server having to perform the full computation.
I guess if implemented client side it might provide a sanity check for the user before submitting, but it's more work for the human and they are almost as likely to get the checksum calculation wrong as any other part of it.
So I would probably remove it.