Comp128-2 and Wireless Providers

[jjjworry]

If a wireless provider uses Comp128-2 with the SIM cards that they provide with phones that are purchased at authorized dealers, can one activate an account with this service provider using a SIM card purchased for another provider which uses Comp128-1?

Of course, the Comp128-1 SIM card is not activated and completely unused and essentially you are providing just the IMEI number that is off the SIM card to the service provider.

Thoughts?

[SirGraham]

Hi jjjworry,

Very good question.

Other question more:
And then operators (wireless provider) that uses a DES function in state of COMP128 (german operators)? More complicated...

I think, there is a mechanish to make the autentification inter-operators. They have a agreement to control this. I think that one operator send this authentication to a server from the other operator. Only if the SIM are from last operator.

However, a few weeks ago, one person tell me this:

This person have a special card SIM (not is a silvercard with SIMEMU, ect...). With this card you can put any IMSI and KI (with a special interface, not GSM 11.11). This card also have the two algoritms (COMP128 v1 y v2) and you can activate one or other. You can works with COMP128 v1 o change and works with COMP128 v2....

He makes this try:

He extract the IMSI and Ki from a card (COMP128 v1 with colission method). He put this IMSI and KI in this card and activate the COMP128 v1 mode. The SIM works well. The same of SIMEMU or others simulators.
but.... e changed the mode and put COM128 v2 with the same IMSI and KI....
...and surprise!!!! The card WORKS WELLl too....

My conclusion:

¿Is It possible that the operators make TWO authentifications with Rand number and KI?
They makes COMP128 v1 and also COMP128 v2...
if one of them is true (the same of the result of the phone)... the authentification is correct....
They need´t knows if one card is COMP128 v1 or v2....

However I ask for a one of the special cards to make more trys....
It´s interesting to knows this things.... :D

Best Regards,
Sir Graham.