Upcoming Events

A comprehensive study of Convergent and Commutative Replicated Data Types

Wednesday, October 25th, 2017 from 7:30pm - 8:30pm SkullSpace: 2nd Floor, 374 Donald Street, Winnipeg, MB, R3B 2J2

This presentation will discuss a simple, theoretically sound approach to eventual consistency. The concept of a convergent or commutative replicated data type (CRDT) will be introduced, for which some simple mathematical properties ensure eventual consistency. A trivial example of a CRDT is a replicated counter, which converges because the increment and decrement operations commute (assuming no overflow). Provably, replicas of any CRDT converge to a common state that is equivalent to some correct sequential execution. As a CRDT requires no synchronisation, an update executes immediately, unaffected by network latency, faults, or disconnection. It is extremely scalable and is fault-tolerant, and does not require much mechanism. CRDTs are used by chat system, collaborative editing systems, and NoSQL databases.

Alex Weber is a Director of BSides Winnipeg, and a co-host of Papers We Love Winnipeg. His day job at Tenable Network Security involves working on the Nessus vulnerability scanner. Alex has a hobbyist interest in cryptography, compilers, and application security.

Peer-to-peer networking with BitTorrent

Thursday, November 30th, 2017 from 7:30pm - 8:30pm SkullSpace: 2nd Floor, 374 Donald Street, Winnipeg, MB, R3B 2J2

Peer-to-peer networking has received a lot of attention due to the battles with the music and movie industries. Despite many beliefs it is not a new concept but, in its simplest form, has existed for over four decades and can be traced back to the original implementation of the Internet. BitTorrent is a distributed peer-to-peer system that uses a symmetric (tit-for-tat) transferring model in an attempt to reach Pareto efficiency. Its protocol employs various mechanisms and algorithms in a continuous effort to try to ensure that there are no other variations in the network arrangement which will make every downloader at least as well off and at least one downloader strictly better off. In its original implementation, BitTorrent bases its operation around the concept of a torrent file, a centralized tracker and an associated swarm of peers. The centralized tracker provides the different entities with an address list over available peers. Later improvements try to remove the weakness of a single point of failure (the tracker), by implementing a new distributed tracker solution.

Andrew Orr is a University of Manitoba Computer Science graduate working in vulnerability research and exploit development. He once read a paper on BitTorrent, and is not very good at writing bios. You can find him on Twitter as @xorrbit.

subscribe via RSS