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I’d add a caveat. Namely that physical SIMs are an excellent security feature, provided carriers aren’t cavalier about managing them. Nowadays US carriers put

I’d add a caveat. Namely that physical SIMs are an excellent security feature, provided carriers aren’t cavalier about managing them. Nowadays US carriers put up a few more hurdles here and there after some highly publicized issues, but it’s still bonkers that I can ultimately just read off the ICCID of a card in my possession and get a number ported to it. Most European carriers don’t allow you to bring your own SIM and will instead only link numbers to SIMs issued to the customer by themselves. That in and of itself would make things safer, but, and this practice varies from carrier to carrier and country to country, often times they require in-person pickup with ID check or courier delivery with ID scan. Although there are also plenty that just send it to the address on file.

fkkffdddd 3y ago
Never heard before this was possible. Do you have some example which carrier allows to bring your own SIM? Ideally, if you have some support page handy that’d explain the process. Honestly, with normal SIM cards this shouldn’t be possible, as you cannot program the keys into the card. There are some eSIM-on-SIM-cards that you could use if your phone isn’t eSIM capable. But again, would be nice to check.
- hpjxohxoyx 3y ago
  you can buy tmo sims off amazon and activate them by id
- eqvinox 3y ago
  > as you cannot program the keys into the card You don't need to program the keys into the card, you program the card's identity/public key into the network.
  - fkkffdddd 3y ago
    Mobile Networks use symmetric keys for mutual authentication. You need the same key both in SIM and the carriers database. What I guess you mean is, you buy an inactive SIM from Vodafone (which has Vodafone-known keys on it), and then you’re telling Vodafone to use that card. By „bring your SIM“ I thought of something non-branded and was surprised. Essentially that is what’s happening with eSIM, hence the need for the provisioning step that also makes transferring hard.
eqvinox 3y ago
> Most European carriers don’t allow you to bring your own SIM Coincidentally, SIM swapping is unheard of in a majority of European countries. ENISA claims about half of European telcos had zero(!) incidents in 2021. (That stat was easiest to find)

fkkffdddd 3y ago

Never heard before this was possible. Do you have some example which carrier allows to bring your own SIM? Ideally, if you have some support page handy that’d explain the process. Honestly, with normal SIM cards this shouldn’t be possible, as you cannot program the keys into the card. There are some eSIM-on-SIM-cards that you could use if your phone isn’t eSIM capable. But again, would be nice to check.

hpjxohxoyx 3y ago
you can buy tmo sims off amazon and activate them by id
eqvinox 3y ago
> as you cannot program the keys into the card You don't need to program the keys into the card, you program the card's identity/public key into the network.
- fkkffdddd 3y ago
  Mobile Networks use symmetric keys for mutual authentication. You need the same key both in SIM and the carriers database. What I guess you mean is, you buy an inactive SIM from Vodafone (which has Vodafone-known keys on it), and then you’re telling Vodafone to use that card. By „bring your SIM“ I thought of something non-branded and was surprised. Essentially that is what’s happening with eSIM, hence the need for the provisioning step that also makes transferring hard.

eqvinox 3y ago

> Most European carriers don’t allow you to bring your own SIM Coincidentally, SIM swapping is unheard of in a majority of European countries. ENISA claims about half of European telcos had zero(!) incidents in 2021. (That stat was easiest to find)