Audit trail

A register is only worth what its record-keeping is worth. Every write is appended to a hash-chained log in which each row commits to the one before it, so a row cannot be altered or removed later without breaking the chain from that point onward. A third party's auditor can verify this themselves, against the data they were given, without having to trust us — and without a blockchain, which would add nothing here and cost credibility in a bank procurement.