[cfontes]

Not directly correlated but I know a old guy that can decrypt EBCDIC and credit card positional data format on the fly. And sometimes it was a "feeling" he couldn't explain it properlly but knew exactly the value, name and other data.

It was amazing to see him decode VISA and MASTER transactions on the fly in logs and other places.

[Rygian]

I've seen that done live, during audits, on live logs on the screen. Needles to say, audit didn't fly first time round (those logs should have been redacted).

[andrepd]

That's got to be the most niche party trick I've ever heard of.

[VoidWhisperer]

I would hope that these logs don't include the full details of the credit card (such as number/cvv).. if it does, the company that is logging this info could end up having some issues with Visa/MC

Edit: Now that I looked at it a little deeper, i'm assuming they are talking about these[0] sort of files?

[0]: https://docs.helix.q2.com/docs/card-transaction-file

[Aspos]

PCI DSS is a relatively new thing. Before it card data flew in the open

[userbinator]

I can do the same with several proprietary network protocols and data formats I've worked on, as well as some x86 Asm - once you start seeing enough of it, you begin to absorb it almost like learning a language.