@cypherdoc:
Neither do I believe that selfish mining is a serious threat. The point I'm trying to make is that given Eyal and Sirer's assumptions, the paper is mathematically correct. You can argue that their assumptions are not realistic (what you appear to be doing), or you can show that they made an error in their analysis (I don't believe they have). Craig Wright did neither.
i've never liked Sirer's SM paper. for instance, i think this is an entirely incorrect assumption on his part which totally destroys his math, p.6:
In the first scenario where the honest nodes succeed in finding a block on the public branch, nullifying the selfish pool’s lead, the pool immediately publishes its private branch (of length 1). This yields a toss-up where either branch may win.
by the time the selfish miner finds out about a new block on the public chain, he's already lost. the public block will have propagated across much of the network making it impossible for the selfish miner to create a 50:50 situation by trying to immediately release it's private block. IOW, he loses the block he's held back and the revenue from it, which is an opportunity cost.
This is what I originally thought until I read the paper in more detail. They do NOT actually assume that the race has 50:50 odds. They solve the problem for all odds between 0:100 and 100:0. This is the γ coefficient in their paper. With γ=1 (the selfish miner wins all races), the selfish mining attack is profitable regardless of the miner's hash power. With γ=0 (the selfish miner loses all races), the selfish mining attack
is still profitable but only if the miner's hash power is greater than 33.3% of the network total. This is summarized in Eyal and Sirer's Fig. 2:
more importantly, miners don't want to destroy confidence in the system which would cause the price to tank.
Yes, I completely agree. The attack only becomes profitable after the difficulty re-adjusts and long after the world has realized that the attack is taking place. I don't think miners would take this risk.
i confronted Sirer about this at the Hasher's United Conference a couple of years ago, not only in the Q&A but also afterwards face to face. he didn't like me then b/c i publicly disagreed with him despite him trying to appeal to authority. he also hasn't liked me since as i have continued to disagree with his work publicly and privately. but i did get him to admit face to face in front of a small group that SM'ing is a huge risk and would be dependent on having full nodes widely scattered across the network that can "listen" for a new public block.
My take on Sirer is that when he first got into Bitcoin, he wasn't taking it that seriously. He came across to us as a total dick after publishing his selfish mining paper (he tweeted that Bitcoin was fatally flawed and that everyone should sell their coins...IMO bad behaviour for a CS professor). Since then, I think he's realized both that Bitcoin is a goldmine for future research and that our community is full of serious researchers and developers who he now respects. I think you two might actually get along if you had met under different circumstances.
not only that, Sirer then goes on to assume even more disastrous behavior from selfish miners;
The selfish miners unanimously adopt and extend the previously private branch, while the honest miners will choose to mine on either branch, depending on the propagation of the notifications.
why would they do that, in effect, doubling down on a losing strategy which will cost them even yet another block on wasted hashing time? answer is, they wouldn't. history has born me out.
I agree again. The Eyal and Sirer model is very simple and doesn't take into account the complexity of human behaviour. But as an academic paper, their work is still correct (given their assumptions) and valueable (given the research and thought they've inspired).