Fault-tolerant Distributed Consensus: The Holy Grail Problem of Distributed Computing

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The fourth and the last talk of Samvaad focusing on ‘Cryptography and Security’ was held at IIITB campus on August 26. The talk was delivered by Dr. Ashish Choudhury, associate professor at IIIT Bangalore, and it revolved around the concept of ‘Fault-tolerant Distributed Computing’, specifically on the problem of distributed consensus.

The talk began with a non-technical introduction to this area, describing the goals of a consensus protocol, the multiple settings in which the problem can be studied and various necessary conditions under which the problem can be solved. Speaking about its application in real-world problems, professor Ashish said, “Distributed consensus protocols can be useful in varieties of real-world problems, such as state-machine replication (SMR), maintaining a distributed database, etc. Ever since its inception, the consensus problem is one of the widely studies research problems, both in the cryptography as well as distributed computing community. The problem has revived renewed interest from various other research communities, thanks to the advent and enormous success of the blockchain technology.

The session went on to discuss about a particular variant of the consensus protocols, namely the class of asynchronous consensus protocols. The motivation for studying asynchronous protocols is that the real-life communication networks like the Internet are inherently asynchronous in nature, where the participating parties are non synchronised.

Dr. Ashish also spoke about the challenges faced while designing asynchronous consensus protocols. The talk ended by discussing some of the key challenging research problems in the domain of asynchronous consensus protocols.

Samvaad, as an initiative, was started in January 2018 to provide a platform and enable a dialogue among the different research initiatives going on at IIIT Bangalore. The initiative features a public talk by one faculty member every week, introducing the ideas and questions that they are pursuing as part of their research. The objective of Samvaad is to enable cross-fertilization of ideas, and develop strategic research collaborations between members of the faculty, as well as with interested external partners.