Sim Lock

d9780

Do you lock your SIM with a pin on a Graphene Pixel the same as with a regular OS set up?

treequell

d9780

I don't personally use the SIM card lock but I believe you can in the same way as on stock OS.

You can find the option under Settings > Security > More security settings > SIM card lock

d9780

treequell

Thank You!!

Graphite

I have done this, yes. SIM locked with a PIN was the same experience as stock Android.
P.S. Always have your PUK ready.

nandohyphen1

How exactly does the SIM lock work and why would someone use it? I mean, yeah it locks the SIM, but what is the purpose for it? Could someone give me a breakdown on how it works? Thank you! :)

that_guy

nandohyphen1 I use it to prevent someone who has stolen my phone from popping out the physical SIM card & putting it in another phone.

ryrona

nandohyphen1 How exactly does the SIM lock work and why would someone use it?

The SIM card is a smartcard, similar to your debit card or credit card. The chip pretty much works the same. The SIM card will sign statements to prove identity, so you can authenticate to the network that you are permitted to use the network. But the SIM card will refuse to do this, unless the SIM card is provided the correct PIN code, which has to be entered on the device the SIM card is currently plugged into. Same as your debit card or credit card.

As for why? Because I don't want someone who has stolen my SIM card or phone with SIM card in to be able to purchase things such as internet services or paid phone calls, that gets automatically billed on my account. Exactly the same reason I want to have a PIN code on my debit card.

A PIN code probably does not matter much for pre-paid SIM cards that are not connected to any bank account, other than that someone who has your SIM card can send SMS messages claiming to be you. But for subscription based SIM cards, you very much would want to have a PIN code.

nandohyphen1 So if I locked my SIM and put it in a brand new phone, my SIM would still have the lock on it and I'd have to enter the PIN to unlock it on the new phone?

Yes.

nandohyphen1

that_guy thank you. That is a really good reason! So if I locked my SIM and put it in a brand new phone, my SIM would still have the lock on it and I'd have to enter the PIN to unlock it on the new phone?

nandohyphen1

ryrona thank you for the breakdown of it. I just discovered that feature in settings and had not ever used it before so I didn't know exactly what it did. Thanks! :)

avaluedcustomer

One reason I turned this off is that I will have to enter two PINs after starting my phone.
The second reason I turned if off: after an automatic reboot, the phone is not reachable (until the SIM PIN is entered)

nandohyphen1

avaluedcustomer when you turn on the phone/ unlock it, does a pop up come up to enter your PIN to unlock the SIM or do you have to go through settings to unlock it?

ryrona

nandohyphen1 when you turn on the phone/ unlock it, does a pop up come up to enter your PIN to unlock the SIM or do you have to go through settings to unlock it?

There's a popup. It is the first thing that show up on your screen after booting the phone, before the regular login screen.

nandohyphen1

ryrona OK cool. I never realized there was such a useful feature on GrapheneOS.

ryrona

nandohyphen1 OK cool. I never realized there was such a useful feature on GrapheneOS.

SIM PIN codes have basically existed on all mobile phone devices since long before smartphones were even invented. Back in the days it was also common to charge your SIM card with actual money which you could then use for paying for phone calls and SMS.

nandohyphen1

ryrona really? That is interesting. I've been looking into the SIM lock feature now. :)

schweizer

What I do not understand is why do I have to enter the sim pin first and then unlock the phone? Would it be the other way round one could store the sim pin on the phone and automatically unlock the sim after first unlock. This would still protect me in case the phone is stolen.

Is there a reason why this is made impossible?

de0u

schweizer Fascinating question. My guesses:

If the phone reboots and is BFU and rings, it is much faster to enter the SIM PIN and answer that to enter a potentially long passphrase and then the SIM PIN.
One might be willing to divulge one's SIM PIN to a colleague or other associate to place a call, but not one's data PIN/passphrase.

schweizer

de0u
I don't think thise are the reasons. Because the phone does not ring before you enter the SIM PIN. That's why a short auto reboot time is dangerous, you risk missed calls.

Second you would still have the same two PIN so you could hand the physical SIM to your collegue. It is basically like leaving the key for the back door in the house when you leave.

Elysium

What I have thought about - in one scenario you may want the phone to boot into airplane mode, which you can't do unless you unlocked your phone, but you are unable to because you need to unlock your SIM card first. So I guess the only way to achieve it is to boot the phone without SIM card first.

Would love to decide myself what to unlock first or have an option to always boot into airplane mode.