# Timewarp attack 600 second grace period **URL:** \ **Category:** Protocol Design\ **Tags:** softfork\ **Created:** [December 17, 2024, 6:31am UTC](https://delvingbitcoin.org/t/timewarp-attack-600-second-grace-period/1326 "2024-12-17T06:31:46Z")\ **Posts on this page:** 1\ **Showing post:** 17
**Author:** ![zawy](https://delvingbitcoin.org/user_avatar/delvingbitcoin.org/zawy/32/750_2.png) [@zawy](https://delvingbitcoin.org/u/zawy)\ **Post date:** [December 25, 2024, 2:37pm UTC](https://delvingbitcoin.org/t/timewarp-attack-600-second-grace-period/1326/17 "2024-12-25T14:37:44Z")
They can’t increase the block rate to get 10% more unless they also have \> 50% and privately mine for 212 periods to reliably keep the MTP held back. Publicly they’d need something like 99%. But if they do a private mine they get 50% more blocks per time than they would publicly after the 1st adjustment for as long as they mine. But they don’t get the 10% gain for the same reason. Delaying 600 s in 1st cycle lowers the difficulty enough for him to get an extra block in the 2nd. But getting 1 more block means difficulty goes up in the 3rd cycle to offset the gain if he doesn’t do the -600 in the next cycle. So he can only maintain getting 1 extra block per cycle. It’s not an advantage that can accumulate. So he gets only 212 blocks which isnt important compared to getting 212 × 2016 excess blocks from doing the private mine (over a public mine). So it’s a 0.05% gain over a private mine and a -3 hour limit is a 0.9% gain. - cycle =\> blocks/cycle at 50% =\> blocks per 2 weeks - 1 =\> 1008 (normal before attack) =\> 1008 - 2 =\> 2016 (private mine begin -3 hr timestamp) =\> 1008 (takes 4 weeks) - 3=\> 2016 (-3 hr) =\> took 2 weeks minus 3 hr due to previous stamp - 4 =\> 2016 (-3 hr) =\> took 2 weeks minus 3 hr He keeps the last timestamp in a cycle at current time. There’s not a way to hold it back or push it forward to help. The only thing he gets over a private mine is more time at the end to mine 1 extra week than he otherwise could have. After 112 cycles he would get a gain of 2 weeks to get 2016 +18 blocks more blocks than doing nothing, less than 2% of the “excess” gains of just being a private mine ( 2016/2 \* 112). I see no reason to dismiss the concerns that -600 will break something. This is my 3rd request that someone explain how it helps. --- _[View the full topic](https://delvingbitcoin.org/t/timewarp-attack-600-second-grace-period/1326)._