In GSM , is Ki specific for each subscriber ?

[ahmed_nasr]

gsm where is ki stored

Hello there ,

Can anybody help me with this ?

I mean is Ki (used in the authentication ) user specific , that is each SIM card has a different Ki and the AUC uses the Ki specific to each user using IMSI-Ki mapping or what's the deal ?

If anybody has a nice explanation for the authentication process too , I would be grateful

Thank you

 

[ahmed_nasr]

kc ki gsm

so ... any help ?

 

[Hammad jamil]

how can i find ki kc gsm

Ki is invidual subscriber idendity key and it is spesific for each subscriber.
now How authentication is done?
i send you a url. if after that u didnot understand than again ask.
https://gsmfordummies.com/encryption/encryption.shtml

 

[Aya2002]

ki process + auc + gsm<

Hi freind I hope this will help you:

Authentication Centre (AUC):
----------------------------------

The AUC is a processor system, it performs the “authentication” function.
It will normally be co-located with the Home Location Register (HLR) as it will be required to continuously access and update, as necessary, the system subscriber records. The AUC/HLR centre can be co-located with the MSC or located remote from the MSC.

The authentication process will usually take place each time the subscriber “initializes” on the system.

Authentication Process:-
-----------------------------
To discuss the authentication process we will assume that the VLR has all the
information required to perform that authentication process (Kc, SRES and RAND). If this information is unavailable, then the VLR would request it from the HLR/AUC.

1. Triples (Kc, SRES and RAND) are stored at the VLR.
2. The VLR sends RAND via the MSC and BSS, to the MS (unencrypted).
3. The MS, using the A3 and A8 algorithms and the parameter Ki stored on the MS
SIM card, together with the received RAND from the VLR, calculates the values of
SRES and Kc.
4. The MS sends SRES unencrypted to the VLR
5. Within the VLR the value of SRES is compared with the SRES received from the
mobile. If the two values match, then the authentication is successful.
6. If cyphering is to be used, Kc from the assigned triple is passed to the BTS.
7. The mobile calculates Kc from the RAND and A8 and Ki on the SIM.
8. Using Kc, A5 and the GSM hyperframe number, encryption between the MS and
the BSS can now occur over the air interface.

Note: The triples are generated at the AUC by:
RAND = Randomly generated number.
SRES = Derived from A3 (RAND, Ki).
Kc = Derived from A8 (RAND, Ki).
A3 = From 1 of 16 possible algorithms defined on allocation of IMSI and
creation of SIM card.
A8 = From 1 of 16 possible algorithms defined on allocation of IMSI and
creation of SIM card.
Ki = Authentication key, assigned at random together with the versions of
A3 and A8.

The first time a subscriber attempts to make a call, the full authentication process takes place.

However, for subsequent calls attempted within a given system control time period, or within a single system provider’s network, authentication may not be necessary, as the data generated during the first authentication will still be available.




Enjoy

 

[Aya2002]

gsm ki

Hi friend
is that enough or you need more?

Thanks