Cum este alocat un număr de telefon la un telefon mobil care nu are S.I.M.?

Cum este alocat un număr de telefon la un telefon mobil care nu are S.I.M.?, adică la telefoane din rețele gen N.M.T., A.M.P.S., N.A.M.P.S. (analogice) și C.D.M.A. (digitală)?

 djl, on 14th December 2010, 12:49, said:

Probabil pe baza de IMEI-ul telefonului sau cum s-o fi chemand codul din interiorul telefonului, aici ma refer la CDMA.
Restul sa explice si altii.

Se numeste ESN si se introduce intr-o baza de date cu ESN-uri si fiecarui ESN ii corespunde un numar de telefon. Cand telefonul e pornit transmite ESN-ul in retea si de acolo mai departe... Daca gresesc cu ceva corectati-ma.

 dan2002sv, on 14th December 2010, 20:11, said:

nu exista IMEI ci IMSI.

CDMA uses a technology called Authentication. Each CDMA phone has a
network set 64-bit (8 digit) number inside of it called an A-key. The a-key
is randomly set by the dealer's computers. After the key is programmed into
the phone, the dealer uses a encrypted dialup to program the ESN and a-key
into the network's authentication center. There is no further record of the
a-key, and it is not visible to any human during this process. The a-key can
be changed by the network over the air in some cases. When this is done, it
uses a 512-bit Diffie-Helleman key agreement algorithm, a strong algorithm
well suited for job. The AcU (authentication center) has knowledge of the
phone's ESN (electronic serial number) and the phone's A-key. The AcU is a
computer inside the MSC. The Tower sends the phone and AcU a random number,
referred to as a RAND challenge. The phone then uses this number, the
phone's A-key and the ESN each as variables in complex calculations. So does
the AcU. These calculations are part of the CAVE(cellular authentication and
voice encryption) encryption algorithm. The result is referred to the SSD_1
(secret shared data, always 64-bits), or the AUTHSIGNATURE. The
AUTHSIGNATURE is then sent to the tower and compared with the AUTHSIGNATURE
the AcU came up with. If the it matches, the phone is authenticated and
allowed to make the call. The tower also uses the SSD_1 to calculate a
pattern of frequencies for the phone and tower to communicate on. Then the
AcU and the phone run the same variables through the other part of the CAVE
to create the SSD_2. This number is then used as a variable in voice
encryption. The CAVE has no known flaws. There is no way to break the
encryption. The A-key and ESN cannot be determined over the air, no matter
how much information is intercepted or obtained over the air. The CAVE
algorithm has also been published and open to public scrutiny. No flaws have
been found. The A-key is kept very secure. The only place it is stored is
in the AuC, and in the handset itself. Unlike the ESN, the a-key isn't
written on the phone, nor viewable through the handset in any way. To
determine the a-key, you must extract the memory chips from the victim's
phone, then use a EPROM reader/writer to do a core dump onto a computer. It
is more logical for a clone to get it from the AcU. Very few people have
access to the AuC, so social engineering would also be extremely hard.

On top of the CAVE encryption, there are several other encryption
algorithms used for communicating information over the air. These algorithms
use the SSD_2 as a variable in their calculations. One is the E-CMEA
(Enhanced- Cellular message encryption algorithm) used for encrypting DTMF
tones. The DTMF tones must be secure because many people use them to enter
credit card numbers while ordering this over the phone. The ORYX algorithm
is used on top of CAVE for encrypting control information, such as tower
handoffs. ( A handoff occurs when you are leaving the range of one cellular
tower and entering another one. The network need to have your phone switch
towers without loosing the call).

On top of encryption and a-key authentication, CDMA uses two other
security measures. The tower can request past call logs from the phone's
stored records and match the phone numbers and times up to the ones in the
tower's call logs. If they don't match, the phone is not authenticated. Also
the network is smart enough to notice if two identical phones are active at
the same time, drop the calls and not authenticate either of them until the
problem is resolved.