Selecting theories and nonce generation for recursive protocols
Klaas Ole Kürtz, Ralf Küsters, Thomas Wilke · 2007
Truderung's selecting theory model is one of the few models of cryptographic protocols which allows to model iterative (recursive) computations of principals and, at the same time, an automatic analysis in the following sense: there exists a procedure that checks whether in all runs of a given protocol a certain message is not revealed to an intruder. A major drawback of Truderung's model is that it allows only a finite number of constants, that is, there is no mechanism by which a principal can generate an unbounded number of fresh tokens such as nonces or session keys. We extend Truderung's model by such a mechanism and show that the extended model still allows an automatic analysis. We also demonstrate that the extended model is more appropriate to model the Recursive Authentication Protocol.