[Cryptography] Cryptography buzzword spotted in mundane life, and I don't know what it means

[Peter Gutmann]

Kent Borg <kentborg at borg.org> writes:

>I noticed something on the receipt I've never seen before, near the bottom is
>this stuff:

That's part of the EMV transaction log, Mike Bond has a nice writeup on it:

https://www.lightbluetouchpaper.org/2009/04/06/a-truly-marvellous-proof-of-a-transaction/

The thinking apparently is that if there's an unusually heavy rain of anvils
at the data centre holding the electronic copy of the transaction then they
can be reconstructed from the printed receipts, except that the printed
receipts typically only hold whatever random fragments of the transaction the
software developer decided to dump there, it assumes that people religiously
file their receipts for however long it takes for anvil showers to pass, and
assumes further that people even get receipts (not sure about how it works
internationally but here you're typically asked if you want a receipt and the
usual answer is "no thanks").  Of the few I've got here there's always an ARQC
present, but the sample size is so small that I don't know if it's
representative.

Anyone know if the EMV agreements require that this protocol core-dump gets
attached to every printed receipt?  I can't see any other good reason for
having it there.

Peter.