this post was submitted on 20 May 2024
379 points (98.0% liked)
Technology
60008 readers
3506 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related content.
- Be excellent to each another!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, to ask if your bot can be added please contact us.
- Check for duplicates before posting, duplicates may be removed
Approved Bots
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
You could store a counter for every machine used on the card, realistically, given few Laundromats would have over 50 or so machines. That'd mean that as you say, restoring the cards initial state would break it for every machine you previously used.
Going way too far now for what would make sense for a Laundromat, but just to entertain the idea...
You could also use an OTP encryption scheme on the card, where the exchange encryption key is based on the laundry machine ID, card ID, and a current timestamp, and thus changes every time the card is used. It would then be quite hard to "restore" the initial state of the card without having the laundry machine's hidden ID. Everything you read off the card would be useless a second later.