4 ms·
Having read bits of the paper and the article I don't get why divisibility by 9 matters. Can anyone ELI-9 this?
by quickthrower2 4y ago
Having read bits of the paper and the article I don't get why divisibility by 9 matters.
Can anyone ELI-9 this?
- horsawlarway 4y agoI haven't done the math, but I believe it's because of two points: 1 - The "difficulty" of mining a block is based on how long it's been since the last block was mined, with a drop off in difficulty at 9 seconds 2 - If two blocks "tie", the the block that was more difficult to mine is the winner, and takes the rewards. --- So essentially, it's a way of breaking ties in their favor - reliably - by cheating a smidge on the timestamps they send for their blocks.
- tromp 4y agoIt matters according to equation (48) on page 7 in the Ethereum design specification [1]. This section specifies how to adjust the difficulty target for each new block. The optimization (I hesitate to call it an attack) identified in the paper could have been rendered ineffective if rounding down (for division by 2048 and by 9) was delayed until after the multiplication in equation (45), resulting in a much smoother adjustment. The so-called "yellow paper" sadly lacks a motivation of all the seemingly arbitrary numbers involved. [1] https://ethereum.github.io/yellowpaper/paper.pdf https://ethereum.github.io/yellowpaper/paper.pdf