# Timewarp attack 600 second grace period

**URL:** <https://delvingbitcoin.org/t/timewarp-attack-600-second-grace-period/1326>\
**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:** 37

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**Author:** ![sjors](https://delvingbitcoin.org/user_avatar/delvingbitcoin.org/sjors/32/59_2.png) [@sjors](https://delvingbitcoin.org/u/sjors)\
**Post date:** [March 31, 2025, 3:19pm UTC](https://delvingbitcoin.org/t/timewarp-attack-600-second-grace-period/1326/37 "2025-03-31T15:19:12Z")

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I’m still trying to understand whether the difficulty decrease compounds. Take the following (same MTP simplification as above):

- Period 0: [0, 0, 0, …, 0, 0, P].
- Period 1: [P-G, P-G, …, P-G, 2P].
- Period 2: [2P-G, …, 3P].
- Period 3: [3P-G, …, 4P],
- …
- Period k: [kP-G, …, (1+k)P].

So each period is stretched by G, causing the difficulty to drop every time. For G = 2 hours, this would be 0.6% per retarget period. That translates to about 15% per year.

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Note that any difficulty decrease accumulation can be reset by an honest miner finding the last block of any retarget period.

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