The ISC International Journal of Information Security

Abstract The spread of rumors, which are known as unverified statements of uncertain origin, may threaten the society and it's controlling, is important for national security councils of countries. If it would be possible to identify factors affecting spreading a rumor (such as agents’ desires, trust network, etc.) then, this could be used to slow down or stop its spreading. Therefore, a computational model that includes rumor features, and the way rumor is spread among society’s members, based on their desires, is needed. Our research is focused on the relation between the homogeneity of the society and rumor convergence in it. Our result shows that the homogeneity of the society is a necessary condition for convergence of the spread rumor.

Abstract Many security protocols have the aim of authenticating one agent acting as initiator to another agent acting as responder and vice versa. Sometimes, the authentication fails because of executing several parallel sessions of a protocol, and because an agent may play both the initiator and responder role in parallel sessions. We take advantage of the notion of transition systems to specify authentication for parallel multiple session's execution. To model the authentication, two main notions called 1. agent's scope and 2. agent's recognizability are introduced, which consider the difference of ability of agents due to their different roles in the protocol and different access to keys and secrets. To formalize above notions, a process algebra provided by some primitives for manipulating cryptographic messages is used. We formalize some security protocols and examine our definition of authentication for them. We just discuss the symmetric key case.