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Ask HN: Why are SIM cards still a thing?

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Re: Ask HN: Why are SIM cards still a thing?

#181

Post by gcb0 »

derefr wrote: post #177
gcb0 wrote: post #176

Earlier quoted context omitted.

yes. the sim has direct access to the radio and other modules, by design. it only needs the actual phone cpu/os for use interface. if it wants to take the radio out of silent mode it can.

That seems like it wouldn't comply with FAA regulations. I always presumed "airplane mode" was the specific set of features required by the FAA to enable the phone to do the same thing as a phone that's off, from the perspective of potential interference with a plane's communications. If the SIM can still enable and use the radio despite "airplane mode" being on, then "airplane mode" is not really "a mode for making…

yes and that is not new.

try this: enable airplane mode and then open any app that has system permission to change gps or Bluetooth or wifi settings. it will enable those radio and the ui will still show the little airplane there.

Re: Ask HN: Why are SIM cards still a thing?

#182

Post by milcron »

gcb0 wrote: post #124
userbinator wrote: post #90

Earlier quoted context omitted.

The SIM card is a smart card If you have a credit/debit card with a chip, look at the arrangement of the contacts and compare to a SIM card. It's essentially the same standard (ISO 7816) at the lower layers, but with different application-layer protocols on top. Also, as a matter of being the only device in posession of the subscriber but arguably owned by the telco, I'd definitely prefer it to be a removable piece w…

/me puts on tinfoil hat the sim card has one important difference. It lives in a device that provides it with 24/7 battery and radio access. That is really worrisome when you think about. A tiny computer running applications you have no idea/access. powered 24/7. Always with you. With access to battery, network, mic, etc. And the other side of the network that could monitor it's traffic for malicious actions is owned…

For tinfoil wearers, the sim card is not as much of an issue as the baseband modem itself.

Re: Ask HN: Why are SIM cards still a thing?

#183

Post by milcron »

derefr wrote: post #177
gcb0 wrote: post #176

Earlier quoted context omitted.

yes. the sim has direct access to the radio and other modules, by design. it only needs the actual phone cpu/os for use interface. if it wants to take the radio out of silent mode it can.

That seems like it wouldn't comply with FAA regulations. I always presumed "airplane mode" was the specific set of features required by the FAA to enable the phone to do the same thing as a phone that's off, from the perspective of potential interference with a plane's communications. If the SIM can still enable and use the radio despite "airplane mode" being on, then "airplane mode" is not really "a mode for making…

You can actually enable wifi yourself even while airplane mode is enabled - try it!

Re: Ask HN: Why are SIM cards still a thing?

#184

Post by zerognowl »

tscs37 wrote: post #128

>Should there not be a software solution that lets you select which network/s the phone should connect to? If I recall correctly german ISPs are trying to find a solution there by embedding the SIM into the device and then branding it on changing provider. The problems SIM cards are (trying) solve is largely to "secure" the phone network. This mostly boils down who to send the large bill when shit goes fan. (The mobi…

"Embedded SIM Design Means No More Swapping Cards" https://mobile.slashdot.org/story/13/12/19/1938254/embedded-...

I am struggling to see the point of embedded SIMs as it defeats the purpose of a SIM card in the first place; that of being portable and transient, of being able to hot swap your phone number to different devices.

Re: Ask HN: Why are SIM cards still a thing?

#185

Post by nucleardog »

derefr wrote: post #177
gcb0 wrote: post #176

Earlier quoted context omitted.

yes. the sim has direct access to the radio and other modules, by design. it only needs the actual phone cpu/os for use interface. if it wants to take the radio out of silent mode it can.

That seems like it wouldn't comply with FAA regulations. I always presumed "airplane mode" was the specific set of features required by the FAA to enable the phone to do the same thing as a phone that's off, from the perspective of potential interference with a plane's communications. If the SIM can still enable and use the radio despite "airplane mode" being on, then "airplane mode" is not really "a mode for making…

It's actually an FCC regulation that prevents people using cellular devices on airplanes, and the issue isn't "interference with avionics" but "violating some fundamental assumptions that the existing cellular network is based on" like devices not travelling 600mph or having the ability to transmit signals for dozens of miles.

Re: Ask HN: Why are SIM cards still a thing?

#187

Post by vidarh »

RandyRanderson wrote: post #102
vidarh wrote: post #25

On the contrary, it is the result of a concerted effort to reduce friction. With SIM cards, users can switch to a new phone by just moving the SIM, or switch to a new provider while keeping their phone (assuming its unlocked) by just replacing the SIM. Prior to SIM cards phones where frequently programmed to be tied to a specific provider. A pure software solution could work, but requires the network operators to be…

Unless you personally know some heads of some major carriers you can't say that and also it's unlikely carriers do things to reduce friction. Unlocked phones are still relatively rare in the US so I don't agree with your second point either. Network operators trust Gemalto, etc to write the SIM card software and also the provisioning and tower software. They also trust the phone manufacturer software as they rigorous…

Yes, I can say that. The history of GSM is well known, and SIMs were introduced because having phones that were programmed specifically for one provider and that needed to be replaced or taken in to a provider to reprogram was seen by everyone including the providers themselves as an impediment to adoption.

> Unlocked phones are still relatively rare in the US so I don't agree with your second point either.

That leaves the vast majority of the world market. The US is not even the largest cellphone market any more, and haven't been for a while.

> They also trust the phone manufacturer software as they rigorously test it before it's pushed to it's subs.

Not GSM network operator has no control over what devices are on their network, just what SIMs are on it. They may or may not have control over their own subscribers, but roaming ensures that any random GSM capable device can appear on their network, E.g. I have some Chinese phone that my network operator probably haven't heard about.

> Note that I have actually worked for some major carriers and have been in discussions with VPs discussing this very issue. See my other answer further down the thread.

Unless said VPs were VPs in European carriers or manufacturers ~30 years ago, when the discussions in CELP and later ETSI led to the adoption of SIMs in the GSM standard, that is quite irrelevant.

Re: Ask HN: Why are SIM cards still a thing?

#188

Post by vidarh »

Dwolb wrote: post #68
vidarh wrote: post #15

Earlier quoted context omitted.

> There's a lot of market momentum around SIM cards and it keeps a telco's offering really sticky. It is more effort for people to swap hardware instead of software. I'd love to see evidence of this. Switching SIMs is something non-technical users do regularly.

I'm afraid I don't have hard evidence. The logic is for normal cell phone use it's more friction to swap a SIM than to have the phone automatically switch network profiles (non-roaming) or for the user to switch network profiles via software setting. For IoT cellular the logic is it's more effort to recall a device and swap a SIM card than to reprovision the SIM profile via a software dashboard. I'm sure we could put…

It takes ~30 seconds to switch SIMs on my phone. Most phones I've had in the last 10 years have had dual SIM slots as well.

It's not swapping the SIMs that provides friction when changing providers.

> For IoT cellular the logic is it's more effort to recall a device and swap a SIM card than to reprovision the SIM profile via a software dashboard.

If you can reprovision it remotely, you're one flaw away from a hacker being able to reprovision it. Meanwhile, the SIM design means there's little reason you'd need to recall it rather than simply send out new SIMs and have users swap them in.

Re: Ask HN: Why are SIM cards still a thing?

#189

Post by eropple »

bogomipz wrote: post #172
eropple wrote: post #166

Earlier quoted context omitted.

Do you happen to know of a good breakdown of how mobile networks work? I'd love to know more, but it's hard to get a handle on it to get started.

Sure: Its helpful to understand the history of mobile/wireless I think since the Telecom industry takes acronyms to an insane level. The terminology changes slightly depending on which generation of mobile is being discussed. This is a good breakdown of the evolution of mobile networks. I think its a good starting point: http://www1.i2r.a-star.edu.sg/~wongtc/EE5406-Network-Archite... This is a good resource for under…

Guess I've got some reading ahead of me. Thanks!

Re: Ask HN: Why are SIM cards still a thing?

#190

Post by candiodari »

brainfire wrote: post #104
shshhdhs wrote: post #100

Earlier quoted context omitted.

Didn't NIST just say two factor via mobile is a "bad idea"? Have Norway or Estonia responded? EDIT: Thank you whoever downvoted an honest question that added to the discussion

The bad idea is being sent a (potentially interceptable) SMS with a code. The Estonian method is described as using a private key present on the SIM card, just like a normal smart card used for authenticating/signing.

That's how every bank I know in Australia, at least 2 US banks and 4 European banks do it. Transfer (sometimes login too) ? Code over SMS.

Besides, pretty much all banks simply use 2 or 3 factor authentication as an anticompetitive tactic (half the businesses in most countries pay the banks 2-300$ per month just for scheduled download of transactions)

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