Hi Zhou, Thank you for your questions.
I guess you are looking at the terminology document from the point of view of writing draft-zhang-hip-privacy-protection-04. You are trying to find the right words to describe the properties of the solution you have been working on. When you look at the privacy consideration draft (see http://tools.ietf.org/html/draft-iab-privacy-considerations-01) then the first thing is to think about a threat model. In your communication protocol you may consider the following adversaries: (Note that I am saying this without having followed HIP for a long time and so I might be missing something here.) * responders who get to see identity information, * eavesdroppers who observe the exchanges and may want to learn about the communication relationships and the identities of the initiator and / or the responders, and * HIP-based intermediaries (e.g., these HIP-based firewalls). Could you explain me what the focus of your draft is with respect to hiding identities? I believe you are not trying to provide a mechanism to prevent disclosing the identity of the HIP initiator to the HIP responder. I think you care about eavesdroppers in the middle. Is this correct? Ciao Hannes From: [email protected] [mailto:[email protected]] On Behalf Of ext [email protected] Sent: Thursday, February 09, 2012 4:51 AM To: [email protected] Subject: [ietf-privacy] anonymity definition in"draft-hansen-privacy-terminology-03" Hi,all the definition of anonymity "Definition: Anonymity of a subject from an attacker's perspective means that the attacker cannot sufficiently identify the subject within a set of subjects, the anonymity set. " 1) is not clear about the content of anonymity set, will the real identities of candidate subjects be included? 2) has too much variance when evaluating a scheme's anonymity. For example, draft-zhang-hip-privacy-protection-04 gives a privacy protection scheme by hashing the real identity: B-HIT-I=SHA-1(HIT-T,N) and send B-HIT-I along with N (chosen for each session). if suppose the attacker has no knowledge of HIT-I, or a set of HIT-I, the scheme has a certain anonymity; if suppose the attacker has knowledge of HIT-I, or a set of HIT-I(which is not difficult to collect), the scheme has no anonymity because he can try each HIT-I he knowes by recalculating SHA-1. The scheme has anonymity at first and has less anonymity with time went on and users have collected more HITs? I think as a character of system, it should be stable. Regards~~~ -Sujing Zhou _______________________________________________ ietf-privacy mailing list [email protected] https://www.ietf.org/mailman/listinfo/ietf-privacy
