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Let G1 be a cyclic multiplicative group of order n. It is known that the computational Diffie--Hellman (CDH) problem is random self-reducible in G1 if φφ( n) is known. That is, given g, gx ∈∈ G1 for some generator g and oracle access to a ''Diffie-Hellman Problem solver'' for g, it is possible to compute g1/ x ∈∈ G1 in polynomial time (with which we can then solve the CDH problem w.r.t. any other generator). On the other hand, it is not clear if such a reduction exists when φφ( n) is unknown. We exploit this ''gap'' to construct a novel cryptographic primitive, which we call an Oracle-based Group with Infeasible Inversion (O-GII). O-GIIs have applications in multiparty protocols. We demonstrate this by presenting a novel multi-party key agreement protocol that does not require interaction between the parties. Instead, the protocol requires each party to query a remote stateless device. Our method relies on the observation that it is considerably more expensive to interact with every party connected via an unreliable network, than it is to query one of several identical stateless devices, some of which may be located in a more reliable sub-network. [ABSTRACT FROM AUTHOR]

This paper presents a model/simulation of a fault tolerant system along with its implementation. The system also keeps track on the performance of the system and adjust it when a need arises. In order for the system to be fault tolerant we have to provide redundancies in the system. This is extremely important for systems, such as supply chain networks, whereby agents communicate with each other and a problem in the system can induce a ripple effect, leading to system-wide outage. Along with speed/bandwidth a need arises for this data flow to be consistent and the mechanism to be fault tolerant. The architecture is based on the concept of grid computing, but in this paper we focus mainly on developing a simulation of the process and develop components, which can monitor the simulation along with providing fault tolerance. Monitoring and fault tolerance are related to each other, as we can't provide fault tolerance without monitoring the system. [ABSTRACT FROM AUTHOR]