4 ms·
most keycards/fobs are pretty secure and near impossible to copy (e.g. NXP Desfire based systems), others are easy to copy but copies can be detected (e.g. NXP
by hnav 3y ago
most keycards/fobs are pretty secure and near impossible to copy (e.g. NXP Desfire based systems), others are easy to copy but copies can be detected (e.g. NXP Mifare Classic), it's mostly legacy RFID stuff that's trivial.
- lxgr 3y agoYeah, but so many hotels seem to use the legacy stuff. Most keycards I've tested don't even register on my phone, meaning that they're using something pre-ISO-14443 (which very likely does not support any real cryptographic authentication).
- tonyarkles 3y ago> it's mostly legacy RFID stuff that's trivial I don't know what it's like globally, but around these parts it is way more common to encounter one of these "legacy" systems than any of the modern stuff. Many large campuses were early adopters of fob-based access and upgrades are prohibitively expensive. One of my favourite attacks against the existing HID-card based systems is... once you scan a card, the 24-bit identifier is split between an 8-bit facility ID and a 16-bit card ID. If you encounter a door that won't open with the card you have, start decrementing the card ID; many of these places assigned card IDs sequentially and by trying smaller IDs you're trying cards for employees who have had longer tenure at the company.