Could you or someone else say how the model that uses the token itself to replace the "proof of work model" works? Which crypto(s) is using this model?
Several of the top 10 cryptocurrencies (by market cap) use "Proof of Stake" (PoS) to replace "Proof of Work". Cardano is one example, but you may not have heard of it, so let's talk about another one. The second largest cryptocurrency, Ethereum, is in the process of transitioning to PoS. This is the one that will likely have the largest impact on reducing energy use and graphics card demand.
Here's a brief excerpt of how PoS makes sense: "Unlike proof-of-work, validators don't need to use significant amounts of computational power because they're selected at random and aren't competing."
System vary. I'm most familiar with Ethereum's, which is the biggest one in production.
It starts with a fairly traditional BFT protocol that reaches consensus as long as everyone follows the rules. These have been known in computer science for decades.
The twist is that if anyone breaks the rules, you can prove they did it. So everybody deposits some ETH as a security bond, and if they break the rules, any other staker can submit proof of that to get a small reward, and inflict a penalty on the offender.
An offense by a small amount of stake does no damage and is assumed to be an accident, so the penalty is small. An offense by enough stake to cause problems is completely destroyed so the attack can't continue.
