I might be wrong but I think it's like this..

A finds a block after 1 minute, then powers off and waits for another minute. They reveal the block after 2 minutes.

B searches for the block for 2 minutes.

After 2 minutes, A has used 1 minute of their compute, and B has used 2.

_heimdall 40 minutes ago | parent | next [-]

In this case A would be at an advantage to spend the 2 minutes looking for the next block. If they happen to find another block quickly they could release then in quick succession.

The benefit there is that if another miner released a block before that 3 minutes this miner still can release their first block and has already spent 2 minutes working on a block that could better validate their first block now that there are competing chains.

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copirate 3 hours ago | parent | prev [-]

But the time spent by B is not wasted. If they find a block between minute 1 and 2, their block will be accepted, and A just lose the reward of the block they found.

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palata 2 hours ago | parent [-]

When you reveal a block, it's not accepted instantaneously. When two competing blocks are revealed "roughly at the same time", it ends up in two competing chains.

If B finds a block between minute 1 and 2, they start working on their competing chain, but A is already working on theirs. And A had a headstart because it started working on it somewhere between minute 1. So it's more likely that A's fork wins the race in the end.

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copirate an hour ago | parent [-]

But the head start doesn't change anything. At this point A is mining on their block, B is mining on theirs. There's no advantage.

I'd even say that B is slightly more likely to keep their reward because they started propagating their block earlier, so it's more likely other miners are mining on this block.

If A finds a second block between minute 1 and 2, then they win, but it would be the same if the didn't withhold their block.

When A is mining on their hidden block, they mine for a potential height of 2 that would win against a miner only able to push a height of 1. But by doing that they put the block they found at risk of being abandoned because another miner found a block in the meantime.

So if you find a block, you get almost 100% chance it'll stay if you publish it immediately. If you withhold it and find another one you get 100% chance of keeping your 2 blocks. If you don't find that 2nd one, you get <50% chance of your block to be the main chain (depending on time of reaction of another block being published, and connectivity). On the other hand, if you don't withhold it and find 2 blocks in a row, you also get almost 100% chance of keeping your 2 blocks. I fail to see how withholding is profitable.

	▲	palata 14 minutes ago \| parent [-]
		> I fail to see how withholding is profitable. Because you keep ignoring the part where it is profitable :-). > If A finds a second block between minute 1 and 2, then they win, but it would be the same if the didn't withhold their block. Except that by withholding their block, they got a headstart so they are more likely to find the second block. So it's not the same. And you keep ignoring the fact that they don't necessarily have to wait until someone else finds a competing block. Maybe a winning strategy is to always withhold the block for 5 seconds. If you slightly increase your likelihood to find the winning block, you increase your profit, and that's the whole point. With the interesting consequence (and that's the game theory part) where if everybody starts withholding their block for 5 seconds, then it changes the winning strategy.