alt Hacker NewsI was hoping the author would also discuss a bit more about the security / encryption side of it. If transactions are done only between the card and the reader, could one use a reader at home to alter the balance? If you can load the card on you phone I assume you can use the phone to read it, but that might not be true.
Anyway it was a great read! Glad to see somebody writing without (obvious) use of LLMs.
Various versions of these cards could be accessed to change the balance, including extracting the key by differential power analysis
[edit] Looks like this finally became public recently https://www.techtimes.com/articles/321138/20260721/japan-con...