A theme in the Post Office (Horizon) scandal is that Fujitsu could amend completed till records after the fact.

From hard copy printouts (receipt rolls?) to cryptography (blockchains), there are technical means to repudiate and reduce risk of amendment.

I'm curious what experiences we've had with them and which ones we should using in retail systems?

I'm also curious how if a privileged user did amend a database, even with an audit log of changes; whether it is likely that a user (lawyer, accountant, manager) would also be alerted to that in their interface.

In paper based accounting, I believe event logs weren't really a thing. The users (accountants) knew the audit history from the records themselves and hopefully today still do: - transaction records was having records for each stage (order, invoice, payment advice, sales receipt, journal entry, credit note, etc) - completeness of records was numbered books, pages, lines - irreversible records was ink pen and stamps - verifiable was entry dates, references to source accounting records, signatures, stamps, double entry and reconciliation reports that could be repeatably generated

Given the mutability of most database systems that support retail environments, do accountants get or need a usable interface to inspect any database changes to completed transactions on top of what a paper system would otherwise give them?