Speaker: Sergey Ozernikov
Affiliation: The University of Auckland
Title: Public-Key Infrastructure: trust metrics in the Web of Trust
Date: Tuesday, 25 Mar 2014
Time: 5:00 pm
Location: Room 412, Science Centre (303)
Public Key Insrastructure (PKI) is an arrangement that provides its users with means for confident and effective utilisation of public-key cryptography. An overview of non-hierarchical example of PKI – Pretty Good Privacy (PGP) – will be given, which uses the concept of a Web of Trust – a structure where any user can act as a certificate authority and assert validity of other users’ certificates.
A user A of PGP before sending a message to another user X must calculate the validity of the other user’s certificate using the public information about the network and their private information about the trustworthiness of the users on the certification paths from A to X. This is normally done on the basis of the so-called trust metric. Trust metrics and decision rules based on them are a field of active research – it is unlikely that anyone will invent a single perfect decision rule since there are many conflicting desiderata. In particular, it is desirable that such a decision rule
– be immune to various attacks;
– be easily computable;
– satisfy nice normative properties (axioms).
This is an introductory talk on this subject. No specific knowledge of cryptography will be assumed. Social networks people are especially invited.