ISO 8583: The language of credit cards

Because no LLM will be able to replace you for quite a while.

On many other payment systems, yes, ISO20022 is or is becoming the lingua franca - e.g. FedWire is going to move next year.

Banks and payment card processing (which is what TFA is about) are basically two different worlds. One switching to a new data interchange format has essentially no consequences to the other.

While I could imagine Visa and Mastercard offering an ISO 20022 interface for new integrations, I’m willing to bet on the majority of volume staying on ISO 8583 for this decade and probably well into the next. They most certainly won’t force anyone to migrate either.

Luckily, there's a bit of everything in the archeological site that is ISO 8583, and field 55 (where EMV chip data goes, and EMV itself is quite ASN.1-heavy, presumably for historical reasons) and some others in fact contain something very close to it :)

[1] https://core.telegram.org/mtproto

Feast your eyes: C99 introduced an ~~abomination~~ feature called flexible array members (FAM), which allows the last member of a struct to be a variable length array.

If you want to ~~gouge you eyes~~ learn more, see section 6.7.2.1.16 [0].

> To add insult to injury, it does not offer a standard way to determine field lengths

That's awful. You can sort of say the same about variable length struts in C, but at least the strict tupe definition usually has a field that tell you the length of the variable length array at the end.

[0] https://rgambord.github.io/c99-doc/sections/6/7/2/1/index.ht...

Finally free tooling doesn't really exist. The connection to the OSI model also didn't help.

I had made up the "ASN.1X", which includes some additional types such as: key/value list, TRON string, PC string, BCD string, Morse string, reference, out-of-band; and deprecates some types (such as OID-IRI and some of the date/time types; the many different ASCII-based and ISO-2022-based types are kept because a schema might have different uses for them in a SEQUENCE OF or SET OF or a structure with optional fields (even though, if I was designing it from the start, I would have not had many different types like that)), and adds a few further restrictions (e.g. it must be possible to determine the presence or absence of optional fields without looking ahead), as well as some schema types (e.g. OBJECT IDENTIFIER RELATIVE TO). (X.509 does not violate these restrictions, as far as I know.)

I also have idea relating to a new OID arc that will not require registration (there are already some, but this idea has some differences in its working including a better structure with the working of OID); I can make (and had partially made) the document of the initial proposal of how it could work, but it should need to be managed by ITU or ISO. (These are based on timestamps and various kind of other identifiers, that may already be registered at a specific time, even if they are not permanent the OIDs will be permanent due to the timestamps. It also includes some features such as automatic delegation for some types.)

There are different serializations formats of ASN.1 data; I think DER is best and that CER, JER, etc are no good. I also invented a text-based format, which can be converted to DER (it is not really meant to be used in other programs, since it is more complicated than parsing DER, so using a separate program to convert to DER will be better in order to avoid adding such a complexity into programs that do not need them), and I wrote a program that implements that.

> Interestingly local real (non-digital) currencies like the Brixton Pound [2] and other local paper scrip seem to escape this

And so do countless other digital (non-real?) payment systems across the globe. That's not to say that there aren't any other security regulations, but they're also most certainly not in PCI scope.

Arguably, the original sin of the card payments industry in particular, and US American banking in general, is treating account numbers as bearer tokens, i.e. secret information; if you don't do that, it turns out that a lot of things become much easier when it comes to security. (The industry has successfully transitioned of that way of doing things for card-present payments, but for card-absent, i.e. online, card transactions, the efforts weren't nearly as successful yet.)

- PCI DSS 4.0 is already in place and to be retired on December 31, 2024. PCI DSS 4.0.1 is the replacement and I place already.

- PCI DSS 4.0.1 and game tokens have nothing in common. The applicability of PCI DSS requirements are decided by card brands, aka Visa, Mastercard, etc. And it is the acquirers to enforce on the third party service providers to enforce the standard. Standard itself has no power on anyone.

- Mastercard and Visa have high stakes because technically they are the regulators. EMV Co, the core of the payments was built by Europay (later acquired by Mastercard), Mastercard and Visa. The M and V of it are managing the chip on cards, online payments and much more. PCI SSC is merely a supervisory authority who sets the standard, the process of assessments and investigations on behalf of these brands.

Side note: While the other card brands accept PCI DSS as an entry level requirement, they do not have as much saying on it as Mastercard and Visa.

Well thats sort of the thing...with Visa and MC, there is an extra layer or two of the bank or Fidelity Information Services. With Amex, they own the full stack end to end.

I wouldn't be surprised if your European bank still relies quite heavily on its mainframes. The mainframe offers high availability, reliability, and, contrary to popular belief, high throughput. Batch processing is just one thing they're good at; real-time processing at high speed is another.

Did you meant Apple Card, Apple Pay or the Apple Store?