Difficulty Bomb Delay to December 2021

FinalStandards Track: Core
Created: 2021-05-06
James Hancock (@madeoftin)
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1 min read

EIP-3554 proposes a delay to the Ethereum difficulty bomb until December 2021. The difficulty bomb is a mechanism that increases the difficulty of mining Ethereum over time, making it more challenging to mine new blocks. This is intended to encourage the transition to a new consensus algorithm, but it can also cause issues if left unchecked. The EIP proposes to delay the difficulty bomb to give more time for the transition to the new consensus algorithm, which is still in development. The delay would also allow for more time to address other issues with the Ethereum network, such as high gas fees and scalability. The proposal has not yet been implemented, and tests have not been completed. There are no known backward compatibility issues, and the delay is unlikely to have security ramifications. Overall, the proposal aims to improve the usability and stability of the Ethereum network by delaying the difficulty bomb and giving more time for development and testing.


PEEPanEIP #39: Difficulty bomb & EIP-3554 with James Hancock


Simple Summary

Delays the difficulty bomb to show effect the first week of December 2021.


Starting with FORK_BLOCK_NUMBER the client will calculate the difficulty based on a fake block number suggesting to the client that the difficulty bomb is adjusting 9,700,000 blocks later than the actual block number.


Targeting for the Shanghai upgrade and/or the Merge to occur before December 2021. Either the bomb can be readjusted at that time, or removed all together.


Relax Difficulty with Fake Block Number

For the purposes of calc_difficulty, simply replace the use of block.number, as used in the exponential ice age component, with the formula:

fake_block_number = max(0, block.number - 9_700_000) if block.number >= FORK_BLOCK_NUMBER else block.number


The following script predicts a .1 second delay to blocktime the first week of december and a 1 second delay by the end of the month. This gives reason to address because the effect will be seen, but not so much urgency we don't have space to work around if needed.

def predict_diff_bomb_effect(current_blknum, current_difficulty, block_adjustment, months): ''' Predicts the effect on block time (as a ratio) in a specified amount of months in the future. Vars used in last prediction: current_blknum = 12382958 current_difficulty = 7393633000000000 block adjustment = 9700000 months = 6 ''' blocks_per_month = (86400 * 30) // 13.3 future_blknum = current_blknum + blocks_per_month * months diff_adjustment = 2 ** ((future_blknum - block_adjustment) // 100000 - 2) diff_adjust_coeff = diff_adjustment / current_difficulty * 2048 return diff_adjust_coeff diff_adjust_coeff = predict_diff_bomb_effect(12382958,7393633000000000,9700000,6)

Backwards Compatibility

No known backward compatibility issues.

Security Considerations

Misjudging the effects of the difficulty can mean longer blocktimes than anticipated until a hardfork is released. Wild shifts in difficulty can affect this number severely. Also, gradual changes in blocktimes due to longer-term adjustments in difficulty can affect the timing of difficulty bomb epochs. This affects the usability of the network but unlikely to have security ramifications.

Copyright and related rights waived via CC0.

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