North American Network Operators Group|
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Re: Vonage complains about VoIP-blocking
On Tue, 15 Feb 2005, Steven M. Bellovin wrote: > The really interesting question, to me, is how to let users provision > their phones to talk to the operator of their choice. The simplest > solution is probably something like a SIM; it would contain the > customer subscription data and the operator's CA certificate. > Switching providers would be as simple as switching SIMs. (Of course, > that assumes that this time we can avoid SIM-locking nonsense....) Like a SIM card, you want to give the authentication information to the user in a form the user can't access themselves. Yes, Virginia the user really is the weakest link. If the user has access to it, in the real world it seems like lots of other people can get access to it. Usernames and N (pick any value for N, it doesn't matter) character static passwords, blech. So how does the user's choice of service provider securely deliver the authentication information to the user's choice of device, without knowing anything about the user or device ahead of time. Physical hardware (i.e. a SIM card) works, and we know the physics involved with its security. But its darn expensive, and people don't like waiting for the mail to deliver it. Most online methods rely on a pseudo-out-of-band authentication method, which usually turns into a version of static password. It should be easy, but it quickly turns into a hard problem to solve.