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Ask HN: Why are SIM cards still a thing?

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41–50 of 191 posts

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

#41

As others have pointed out, SIM cards are basically smart cards. There's PKI, private keys, the ability to perform mutual authentication (although that's not usually done, at least in .us), and much more. Honestly, I wish their use would expand into other areas of our lives -- replacing username and password combinations for various devices (working for an ISP, home routers are one good example). As much as I'm again…

The national ID thing happened long ago, the thing that is on the verge of happening is 100% digital communications and interaction with the government.

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

#43

The SIM card is a smart card, i.e. a secure piece of hardware, that protects the telephone network from the subscriber - most importantly, it ensures that the network has someone to bill. In most western countries, SIMs do little else; however, they are full application platforms, allowing stuff like Kenya's mobile payment network https://en.wikipedia.org/wiki/M-Pesa . For what it's worth, you really don't want to ha…

Doesn't every login form on the web also protect the respective operator from the subscriber? Why can't a "software SIM" simply be a username and a password? My explanation is that it's difficult to change something that literally the entire world uses.

Because username and password is a disaster for security. It's sole purpose is let ANY guy ANY where on the planet connect to your account.

SIM cards are cryptographic hardware tokens. They are much more secure than passwords.

In fact, they do need a password as well on top of the hardware token, that's the 'PIN code' you have to enter when you (re)boot your phone.

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

#44
I work in the industry. I somewhat agree with you, SIM cards are a hassle, and I hope they will go away at least partially.

As for why you still need them, I see some reasons:

1. The alternative may be worse. At least with SIM cards you can switch operator when you want (if the phone is not carrier locked, bleh), or use a local prepaid SIM when abroad.

2. Inertia. Removing the physical SIM would require getting operators and phone manufacturers to coordinate.

3. The IM card is what securely identifies the owner of a phone number, and makes sure they are not two phones with the same number. With a software SIM, if it is done wrong, you risk getting malware that steals your phone number.

Personally, I think we will eventually see SIM-free data only connections without a phone number. You really should be able to buy an LTE tablet, get online and just pay for some data. Apples has been trying a bit with the Apple SIM, but it is US only, and only works with a few operators.

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

#45

> Feels like this is probably the result of telco networks wanting as much friction as possible to change providers No, it is the opposite. It is exactly done like this so you only need to get the sim card and not need to have the operator decide for you (of course people shoot themselves in the foot by signing a long term contract while getting a locked mobile phone)

I imagine one of the main reasons it was done like this was because when the GSM standard was designed, a non-insignificant number of phones were fixed mounted into cars (due to the sheer bulk), and then being able to bring your smartcard with you in your wallet and swap between phones (cars) would be a very handy feature.

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

#46
There is actually an eSIM (embedded sim) specification (http://youtu.be/mLouo2mYjAU) that was released quite a while ago by the GSMA and its mostly up to the device manufacturers and carriers to implement it now.

It lets you virtually subscribe to a network, so for example if you're traveling, you don't need a local card just pop up some software and choose a new network.

Apple already has some devices that implement it, AFAIK, the iPad Pros use this. Apple calls it Apple SIM (https://techcrunch.com/2016/03/23/explainer-alert-heres-what...)

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

#47
post #39

The SIM card is a smart card, i.e. a secure piece of hardware, that protects the telephone network from the subscriber - most importantly, it ensures that the network has someone to bill. In most western countries, SIMs do little else; however, they are full application platforms, allowing stuff like Kenya's mobile payment network https://en.wikipedia.org/wiki/M-Pesa . For what it's worth, you really don't want to ha…

In Estonia, you can use your SIM to create a government recognizeed digital signature. [1] Thus, you not only identify yourself to the mobile operator, but you can also identify yourself to banks, government services, and more. [1] https://e-estonia.com/component/mobile-id/

The same idea is used in Norway. Most banks and public services (e.g. tax returns) use this system for online two-factor authentication.

[1] https://www.bankid.no/en/

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

#48

The SIM smartcard is a cryptographic device that prevents people from stealing/copying/hijacking/cloning other phones/accounts/billing/credit/etc. Each SIM has a unique ID that is used to track/bill/identify your phone.

> Each SIM has a unique ID

To be more precise, the SIM is actually a crypto CPU that stores a private key, and can perform crypto using that private key on behalf of the phone, without betraying the key itself.

This is also how Chip-and-PIN debit/credit cards are designed to work (so that a rogue terminal/skimmer can't just clone the card number), although there are various real-world implementation flaws with most of those.

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

#49

Earlier quoted context omitted.

Doesn't every login form on the web also protect the respective operator from the subscriber? Why can't a "software SIM" simply be a username and a password? My explanation is that it's difficult to change something that literally the entire world uses.

Because username and password is a disaster for security. It's sole purpose is let ANY guy ANY where on the planet connect to your account. SIM cards are cryptographic hardware tokens. They are much more secure than passwords. In fact, they do need a password as well on top of the hardware token, that's the 'PIN code' you have to enter when you (re)boot your phone.

Most of the internet runs on usernames/passwords. I understand that a hardware token (with a PIN) is more secure. But is it worth the added complexity?

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

#50

Earlier quoted context omitted.

Doesn't every login form on the web also protect the respective operator from the subscriber? Why can't a "software SIM" simply be a username and a password? My explanation is that it's difficult to change something that literally the entire world uses.

Who would you want to hold your 'software SIM' username and password? What's to stop someone else from logging in to your account once they have your credentials?

I have hundreds of usernames and passwords for various web sites and don't see a problem in having one more(?)
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