My Presentation on Proof-of-Work vs. Proof-of-Stake Blockchain Protocols

I gave a talk in our seminar about the proof-of-work vs. the proof-of-stake blockchain paradigm. Although I don’t have an audio/video recording, here is a Google Slides rendering of my original Powerpoint slides. Some of the animations are out of place/order, but in general, it feels okay.


I intended this talk to be accessible in nature, so I intentionally skipped many details and strived not to flaunt any equation in it.

Advertised Summary: Bitcoin is a blockchain protocol where finalized transactions need a “proof of work”. Such protocols have been criticized for a high demand for computing power i.e., electricity. There is another family of protocols which deals with a “proof of stake”. In these protocols, the ability to make a transaction depends on your “stake” in the system instead of your computing power. In both cases, it is notoriously difficult to mathematically prove that these protocols are secure. Only a handful of provably secure protocols exist today. In this talk, I will tell a lighthearted story about the basics of the proof-of-work vs. proof-of-stake protocols. No equations but a lot of movie references.

 Please enjoy, and please let me know your questions and comments.


4 thoughts on “My Presentation on Proof-of-Work vs. Proof-of-Stake Blockchain Protocols

    1. Hey Kirill, which permission are you referring to? The presentation is right there. I didn’t put any kind of permission check.

      However, I just realized that the fullscreen is not working. By a quick google search, it seems like a WordPress issue.

  1. Saad, in this presentation you reference Ouroboros Thoosa – is it the same as the recent paper Ouroboros Genesis? I coudn’t find papers about Thoosa.
    Also I couldn’t find “Simplificaiton of Ouroboros” paper

    1. Hi Kirill, sorry, I saw your comment only now.

      No, Thoosa is not the same as the Genesis, we’re still working on it. Here, we’re focusing at the generating randomness in a distributed way. Since the random nonce generated at the current epoch determines the slot leaders at the next epoch, an unbounded adversary may launch a grinding attack to influence the nonce so that the leader election works in his favor.

      In Thoosa—not sure if we’ll keep this name going forward—we are modeling several nonce-generating schemes and analyzing their security against an unbounded grinding attack.

      Such schemes may run on top of a blockchain protocol, or in general, may be run as a standalone scheme.

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