One thing I absolutely don't understand about telecom security is how, in 2025, we're still using pre-shared keys in our mobile phone standards.
RSA and Diffie Hellman[1] have existed for decades, so have CA systems, yet SIM cards are still provisioned with a pre-shared key that only the card and the operator knows, and all further authentication and encryption is based on that key[2]. If the operator is ever hacked and the keys are stolen, there's nothing you can do.
To make things even worse, those keys have to be sent to the operator by the SIM card manufacturer (often a company based in a different country and hence subject to demands of foreign governments), so there are certainly opportunities to hack these companies and/or steal the keys in transit.
To me, this absolutely feels like a NOBUS vulnerability, if the SIM manufacturers and/or core network equipment vendors are in cahoots with the NSA and let the NSA take those keys, they can potentially listen in on all mobile phone traffic in the world.
[1] I'm aware that those algorithms are not considered best practices any more and that elliptic curves would be a better idea, but better RSA than what we have now.
[2] https://nickvsnetworking.com/hss-usim-authentication-in-lte-...
RSA and Diffie Hellman[1] have existed for decades, so have CA systems, yet SIM cards are still provisioned with a pre-shared key that only the card and the operator knows, and all further authentication and encryption is based on that key[2]. If the operator is ever hacked and the keys are stolen, there's nothing you can do.
To make things even worse, those keys have to be sent to the operator by the SIM card manufacturer (often a company based in a different country and hence subject to demands of foreign governments), so there are certainly opportunities to hack these companies and/or steal the keys in transit.
To me, this absolutely feels like a NOBUS vulnerability, if the SIM manufacturers and/or core network equipment vendors are in cahoots with the NSA and let the NSA take those keys, they can potentially listen in on all mobile phone traffic in the world.
[1] I'm aware that those algorithms are not considered best practices any more and that elliptic curves would be a better idea, but better RSA than what we have now.
[2] https://nickvsnetworking.com/hss-usim-authentication-in-lte-...