Priority of Service

Virtually all wireless carriers can, but in practice few do (largely because it's easy to "hack" access priority in the older ways of doing it, such as Access Overload Class in phones that do AMPS.) T-Mobile in Washington DC (GSM, so no AMPS AOC to deal with) has a true priority system in operation.

-SC

 

At my last company we could do it, but we refused request from the local gov'ts for that feature...basically the way it would have worked on our "small" cdma network, we would have turned off the other customers access to the system and left the priorty users on....that's asking for a lawsuit.

 

Yes, I believe T-Mobile as a GSM provider is a Priority service. I have even heard many many times that that's what the Presidents and people close to them use, as it is the most secure.

 

So you are saying that the president of the United States uses T-Mobile, a company owned by Deutsche Telekom AG ...which is owned 45% by the German Government.


And you actually believe yourself as your typing this? Or are you just trying to pull my leg?

 

It was said that President Clinton and Family used GSM mobile service, and at that time, T-Mobile was the only GSM provider, no AT&T or Cingular; So yes, that is what I'm saying. They do use T-Mobile.

 

Wasn't powertel still around while Clinton was in office? I'm not sure if powertel was in the DC area or if it was some other carrier that T-Mobile bought.

Whoever... was Tmobile actually operating in the US at that time? And even if Clinton was using it, that doesn't necesarily mean Bush is.

 

There was no Powertel in D.C. It has always been Voicestream I believe. It was some Sprint spectrum, before they decided to go CDMA. I'm sure it's not really up to each individual president what they use; They use what they are told is secure.

 

I just tried to find a relevant news article, but couldn't ... however, I could have sworn that George Bush and company used Sprint PCS because he really liked the handsets that were available (I'll keep comments about kids and their toys to myself

ATLguy

 

Maybe Bush does use Sprint PCS, but I'm just telling you what I heard Clinton and Family used. They used GSM, because it is the most secure.

It seems like it would be in Bush's best interest to use it too, but I maybe it's his option.

 

First, let me apologize if this gets too technical, but after all, that's what this is for, right?

Regardless of what the president uses for his personal phone, GSM is not more inherently secure as far as I know. I believe both systems incorporate reasonably strong encryption, though the providers may not turn them on. If I remember correctly, GSM has this system where it calculates a TMSI (temporary somthingorother) after it gives some sort of identifying information (IMSI, IMEI... whathaveyou). As I recall, the TMSI is used to identify the phone, but the stuff is encrypted with one of the original values (IMSI, IMEI,....), thus without hearing the initial issuance of the TMSI (which could have happened months ago) you'd have no idea what key to use. In addition there's a secure key on the SIM that is used to authenticate and encrypt data.

CDMA systems, on the other hand by their very design encode and interleave outgoing frames based on a number of different factors, including the ESN (electronic serial number, ~IMEI) of the phone. In addition, this information is used to determine things like channel assignment. In addition to that, like the GSM solution, each phone has an A-Key which cannot be changed and is never transmitted which is used in the authentication/key generation process for encrypting the data.

That's the air interface side of the argument. Inherently, due to the way information is transmitted over the spectrum, CDMA is clearly more secure. The way power control is done means that you have to be more or less in line to the basestation to receive a signal. Signals, too, are much weaker than they need to be for GSM, as its a spread spectrum technology. Its the same reason that the US government used it for its classified networks.

Besides, do you think the president really has classified conversations over a network that isn't controlled by the government (i.e. Verizon, T-Mobile, whathaveyou?)

So, that's my argument, complete with handwaving. Anybody with more experience in either of the two systems want to correct/add to what I've said?

Here are links opining that CDMA is more secure than GSM:
[mcommerce Times
SkyTEL

And the kickers:
GSM Hacked due to Weak Algorithms
Evesdropping on CDMA networks

 

There is a link that you left out, that talks about how GSM has stepped up it's security. I will try to find it, but it clearly states that GSM is more secure.

 

What is this becoming? a GSM vs CDMA competition? For me, a regular US citizen, and I am sure for all of you also, both technologies are secure enough.