Goals for Authentication and Key Establishment

Abstract

Any attack on a protocol is only valid if it violates some property that the protocol was intended to achieve. In other words all attacks must be consid­ered relative to the protocol goals. Experience has proven that many protocol problems result when designers are unclear about the protocol goals they are trying to achieve. This in turn leads to disputes about whether protocol at­tacks are valid, since designers may regard the goals differently from analysers. Gollmann [118] has recognised that it is a difficult matter to decide exactly what is meant by commonly used words such as ‘authentication’; even though everyone has a general idea of the meaning of such a word, the actual interpre­tation may vary with the protocol. It turns out that although most authors can agree on general definitions, their ideas diverge when precision is required.