Is there any usualy used protocol to interconnect AuC with HLR? (because this is only feasible way to connect AuC with HLR from different producer)
About algorithms A3, A8 I have found that they are not strictly standardized. There exist only some proposals that are available from GSM forum. As I suppose the specific algorithm (A3, A8) is negotiated between operator and SIM card supplier. Can anybody confirm this guess? Another question arise: Is it usual that one operator uses more than one type of A3, A8 algorithms – different version of SIMs??? Why? – different level of security???