On the Versatility of Bracha’s Byzantine Reliable Broadcast Algorithm

G. Bracha presented in 1987 a simple and efficient reliable broadcast algorithm for [Formula: see text]-process asynchronous message-passing systems, which tolerates up to [Formula: see text] Byzantine processes. Following an idea recently introduced by Hirt, Kastrato and Liu-Zhang (OPODIS 2020), instead of considering the upper bound on the number of Byzantine processes [Formula: see text], the present short article considers two types of Byzantine behavior: the ones that can prevent the safety property from being satisfied, and the ones that can prevent the liveness property from being satisfied (a Byzantine process can exhibit only one or both types of failures). This Byzantine differentiated failure model is captured by two associated upper bounds denoted [Formula: see text] (for safety) and [Formula: see text] for liveness). The article shows that only the threshold values used in the predicates of Bracha’s algorithm must be modified to obtain an algorithm that works with this differentiated Byzantine failure model.

Secure Remote Biometric Authentication Protocol

The secure remote biometric authentication protocol proposed in this paper solves the problem from the nature of the biometric data. The proposed protocol preserves the privacy of the users biometric data when it is transmitted in the protocol. The liveness property of the protocol guarantees that the biometric data used to authenticate the user comes from the live presentation of the user. The most important property related with the intentional authentication; it confirms that the purpose of the user authentication correspondences to the users purpose. The proposed secure remote biometric authentication protocol promises three properties so that the user is confident with the security level that the protocol offers and it guarantees that the protocol does not manipulate with an intruder.

Mixed Integer Programming-Based Liveness Test for FMS with Full Routing Flexibility

Mixed integer programming (MIP) is an important technique to verify the liveness property of sequential flexible manufacturing systems (FMS) modeled by Petri nets. When there are some fully flexible routings in FMS, the existing MIP-based methods are not suitable for testing their liveness. This paper defines a subclass of S*PR nets firstly, namely, OSC-S*PR nets, and concludes that an OSC-S*PR net is live if there exist no non-max′-controlled siphons. Accordingly, determining whether or not an OSC-S*PR net is live can also be realized by using standardized mixed integer programming (MIP) tools. Furthermore, the liveness property of S*PR nets can be tested in two steps: first, for a given S*PR net, constructing an OSC-S*PR net to ensure that if the latter is live then the former must be live; second, testing liveness of the constructed OSC-S*PR net by the aforementioned MIP-based algorithm. In the end, the performance of the method is demonstrated by an application of FMS.