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?
There is also a lot of “security by obscurity” in the corporate/fintech world - “it’s open source so everyone can see the code which makes it less secure”. The inverse is often true thanks to Linus’s Law.
The article you linked seems to suggest that Linus’s Law is a mere suggestion, at best.
No one is suggesting that open source is inherently less secure, just that the vulnerabilities are easier to find, and thus easier to get exploited. For a third party reviewer there’s a lot of incentive not to report bugs they would find in banking software.
Unfortunately, I’ve met a number of people who genuinely do believe this! The same demographic who don’t know how copy and paste works or take photos of stuff on their monitor instead of print-screening and tend to end up running large corporations even though they’re completely out of touch.