Blockchains and the commons

Blockchain phenomena is similar to the last century gold rush. Blockchain technologies are publicized as being the technical solution for fully decentralizing activities that were for centuries centralized such as administration and banking. Therefore, prominent socio-economical actors all over the world are attracted and ready to invest in these technologies. Despite their large publicity, blockchains are far from being a technology ready to be used in critical economical applications and scientists multiply their effort in warning about the risks of using this technology before understanding and fully mastering it. That is, a blockchain technology evolves in a complex environment where rational and irrational behaviors are melted with faults and attacks. This position paper advocates that the theoretical foundations of blockchains should be a cross research between classical distributed systems, distributed cryptography, self-organized micro-economies, game theory and formal methods. We discuss in the following a set of open research directions interesting in this context

HDEER: A distributed routing scheme for energy-efficient networking

The proliferation of new online Internet services has substantially increased the energy consumption in wired networks, which has become a critical issue for Internet service providers. In this paper, we target the network-wide energy-saving problem by leveraging speed scaling as the energy-saving strategy. We propose a distributed routing scheme-HDEER- to improve network energy efficiency in a distributed manner without significantly compromising traffic delay. HDEER is a two-stage routing scheme where a simple distributed multipath finding algorithm is firstly performed to guarantee loop-free routing, and then a distributed routing algorithm is executed for energy-efficient routing in each node among the multiple loop-free paths. We conduct extensive experiments on the NS3 simulator and simulations with real network topologies in different scales under different traffic scenarios. Experiment results show that HDEER can reduce network energy consumption with a fair tradeoff between network energy consumption and traffic delay

Packet Efficient Implementation of the Omega Failure Detector

International audienceWe assume that a message may be delivered by packets through multiple hops and investigate the feasibility and efficiency of an Omega Failure Detector implementation. To motivate the study, we prove the existence and sustainability of a leader is exponentially more probable in a multi-hop than in a single-hop implementation. An implementation is: message efficient if all but finitely many messages are sent by a single process; packet efficient if it is message efficient and the number of packets used to transmit all but finitely many messages is proportional to the number of processes in the system; super packet efficient if it is message efficient and the number of channels used to transmit all but finitely many packets is proportional to the number of processes in the system. We prove that a super packet efficient implementation of Omega is impossible. We establish necessary conditions for the existence of a packet efficient implementation of Omega and present an algorithm that implements Omega under these conditions