cross-posted from: https://fost.hu/post/226135
Let’s say, I create a bank with the caveat that all of my banking phone apps and webapps are FOSS (or if they depend on non-free components — banks probably do to communicate with each other —, then just OSS). Am I going to be behind the competition by doing this?
If the most secure crypto algorithms are the ones that are public, can we ensure the security of a bank’s apps by publicizing it?
Are they not doing this because they secretly collect a lot of data (on top of your payment history because of the centralized nature of card payments) through these apps?
EDIT: Clarifying question: Is there a technical reason they don’t publicize their code or is it just purely corporate greed and nothing else?
It wouldn’t matter much.
Most of what a bank does isn’t on your phone, but server side.
In fact most bank apps could be replaced with an internal web browser that is pointing at their website, and a password manager, with no loss in functionality or change in security.
And if you’d like to review the client side code the bank is using you can just open dev mode in your browser, right now.
OP raises a good point, though. Why isn’t there a standard banking API that all banks could use, against which applications could be written?
People don’t choose banks because of the bank’s app. Banks are also pretty sticky. Having a standard would allow banks to save money on application development. I just don’t see what the value-add of proprietary banking APIs are for them. It doesn’t seem like much of a differentiator.
I think there’s a sort of standard in the EU; why doesn’t the US have one?
Are there any downsides to opening up the server-side code too? Would it also compromise other banks’ security, since these banks need to interoperate?
It would be unwise for a bank to publish its exact fraud detection and risk management policies, otherwise they could be easily circumvented. A lot of these policies will be embodied in their internal backend services.
Someone will now inevitably mention “security by obscurity”. But Kerckhoff’s Principle is specifically about cryptosystems which should derive their security solely from the strength of the keys. That way, confidentiality is still ensured even when details about the cryptosystem become known to adversaries.
But non-cryptographic aspects of security benefit from asymmetric knowledge, from grey areas, from increasing risk for adversaries.
Yeah I thought you’d ask this. Basically they’ll never do this, just because their attitude is “fuck you I’m a bank”.
Beyond this, there’s a big difference between source code and having a working system.
For very long running systems their state depends very heavily on how they were maintained, little bits of informal design decisions that get components working together, and the order stuff was loaded in, and what other services were up and running when you booted up.
None of this magic is captured by source code, and it can make even setting up a replacement server, even as part of the same infrastructure really hard.
Of course banks are moving to more modern dev methods that encourages turnkey deployment, but the fact that they still rely on a bunch of COBOL code tells you there’s a lot of very old system running in “do not touch” mode
Remember that banking and finance is full of regulations, and have moving speed of snail. Opposite of IT. When asked for something like this (open source or cross compatibility or anything nerdy) the first question is “who will be liable for losses and damages when something breaks?”.
Liability is probably the biggest factor. When something isn’t working properly, they want to be able to point fingers at someone and blame them. The vendor then blames someone else. Open source tends to be the polar opposite, which means huge red flags - hippie stuff, no payment, no liability, no pointy-blaming game.
Or so I’ve heard from people working in that sector. For places as conservative as them to deploy FOSS solutions, you’ll need the government branches cooperating with clearly worded laws and regulations, dragging them kicking and screaming into adoption.
And that’s assuming no one will lobby against in the process.
