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AFAIK, a SIM card itself has a card id (ICCID), which should not be changed and is not used often. The subscriber id (IMSI) is in the "application" layer of the
by labawi 6y ago
AFAIK, a SIM card itself has a card id (ICCID), which should not be changed and is not used often. The subscriber id (IMSI) is in the "application" layer of the card and theoretically could be changed by the provider, or as a speciality, multiple ones installed.
That being said, I've never actually seen a card's IMSI changed. They usually give you a new sim and IMSI, even for a replacement card.
- extrapickles 6y agoMost SIM cards are one-time programmable, so they can’t change anything on the card. They do still have a small RW area, but thats generally for user data (contacts). You can get SIM cards that have large amounts of storage for running applets and have better support for OTA, but most carriers don’t like the extra expense.
- dogma1138 6y agoAren’t most SIM cards today use over the air provisioning since networks employ thin provisioning theses days?
- GekkePrutser 6y agoYes they do almost all support it (with many security vulnerabilities as a result, Karsten Nohl did a really great presentation on this at OHM2010). But the IMSI is almost always provided at manufacture time. I think it's also because the card would not be able to be provisioned over the air without getting connected to the network first, and without an IMSI there is no network connection :)