I find the whole problem statement mysterious. The stated problem is, "How do I find a person's SIP URI without having them present to ask?" and "How do I prevent unauthorized people from obtaining this information?"
The first part is a general phone book problem. But by hypothesis, it requires relatively little authentication of me to obtain the SIP URI. Yes, you can propose a step where the inquiry is passed to the target for approval, but that means that anyone who attempts a lookup can annoy the target person -- a direct failure of the privacy goal, since the inquirer has just contacted the target! If you want people to be interested in this, you're going to have to assemble a much better problem statement and at least one plausible solution, I think. My suspicion is that treating the SIP URI itself has having strong privacy requirements, but not treating the information needed to look up the SIP URI as not having strong privacy requirements, is not going to make any difference unless the process that maps between the two has strong authentication of the inquirer. Dale _______________________________________________ Sip mailing list https://www1.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
