The epistemics of encryption
A.M. Bleeker, D.J.N. vanEijck · Centrum Wiskunde & Informatica (CWI), the national research institute for mathematics and computer science in the Netherlands · 2000
Message passing by means of public key encryption is described in terms of doxastic dynamic logic. A secret message from a to b can have as eect that b learns something new from a, but it can also cause a change in the real world, when the contents of the message forces b to cease trusting a. As a tool for analysing secret message passing (and much else besides) we develop a framework that allows changes of states conditioned by beliefs about those states. 1 Introduction We present a model for describing how changes in the world get reected in multi-agent doxastic settings. One of the applications is the description of the results of message passing, where messages can be public announcements, limited access announcements, or secret communications. Message exchanges can result in belief updates, but also in changes of attitude towards the sender. Our model can also deal with adjustments of agents to a changing reality, collaborations between agents to achieve common goals, and much ...