Difficulty Bomb Delay to June 2022

Delays the difficulty bomb to be noticeable in June 2022.
FinalStandards Track: Core
Created: 2021-10-05
Tim Beiko (@timbeiko), James Hancock (@MadeOfTin), Thomas Jay Rush (@tjayrush)
DiscussionsOriginal linkEdit
1 min read

EIP-4345 proposes to delay the Ethereum network's difficulty bomb until June 2022. 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 from proof-of-work to proof-of-stake consensus, which is more energy-efficient. However, if left unchecked, the difficulty bomb can make mining nearly impossible, which would grind the network to a halt.

The proposed delay would give developers more time to implement the necessary changes for the transition to proof-of-stake. It would also prevent the network from becoming unusable in the meantime. The delay would be achieved by adjusting the block timestamp, which would slow down the increase in mining difficulty.

EIP-4345 is consensus-compatible, meaning it would not cause a hard fork in the Ethereum network. It is also backward-compatible, meaning that nodes running older versions of the software would still be able to participate in the network.

Overall, EIP-4345 is a necessary step to ensure the smooth transition of the Ethereum network to proof-of-stake. By delaying the difficulty bomb, developers have more time to implement the necessary changes, and users can continue to use the network without interruption.


PEEPanEIP#54: EIP-4345: Difficulty Bomb Delay to June 2022 with T Jay Rush



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 10,700,000 blocks later than the actual block number.


Targeting for The Merge to occur before June 2022. If it is not ready by then, the bomb can be delayed further.


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 - 10_700_000) if block.number >= FORK_BLOCK_NUMBER else block.number


The following script predicts a ~0.1 second delay to block time by June 2022 and a ~0.5 second delay by July 2022. 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 for predictions: current_blknum = 13423376 # Oct 15, 2021 current_difficulty = 9545154427582720 block adjustment = 10700000 months = 7.5 # June 2022 months = 8.5 # July 2022 ''' 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(13423376,9545154427582720,10700000,7.5) diff_adjust_coeff = predict_diff_bomb_effect(13423376,9545154427582720,10700000,8.5)

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.

In this specific instance, it is possible that the network hashrate drops considerably before The Merge, which could accelerate the timeline by which the bomb is felt in block times. The offset value chosen aimed to take this into account.

Copyright and related rights waived via CC0.

Further reading
Anyone may contribute to propose contents.
Go propose
Adopted by projects
Anyone may contribute to propose contents.
Go propose

Not miss a beat of EIPs' update?

Subscribe EIPs Fun to receive the latest updates of EIPs Good for Buidlers to follow up.

View all
Serve Ethereum Builders, Scale the Community.
Supported by