Difficulty Bomb: Ethereum's Increasing Difficulty in Mining

What Was the Difficulty Bomb?

Ethereum launched using the proof-of-work consensus mechanism, an algorithm that uses large amounts of energy and computational power. This mechanism encourages mining and thus reward-focused centralized mining farms. However, this centralization goes against the original decentralization tenet behind cryptocurrency.

Ethereum's "difficulty bomb" referred to the intentional and sudden increase in mining difficulty on the blockchain. It was released to coincide with the blockchain's transition to proof-of-stake. The intent behind the difficulty bomb was to exponentially increase the amount of time it took to mine a new block on the Ethereum blockchain so that it:

  • Encouraged cryptocurrency miners to move away from energy-intensive proof-of-work mining by removing the incentive
  • Took away the ability to centralize currency creation and ownership
  • Discouraged blockchain forks
  • Forced node upgrades

Key Takeaways

  • Ethereum’s “difficulty bomb” referred to a sudden increase in mining difficulty to discourage miners from opting to stay with the proof-of-work mechanism after it transitioned to proof-of-stake.
  • Difficulty refers to the time and computational power needed to verify a cryptocurrency's transactions within a blockchain under the proof-of-work mechanism.
  • Ethereum's difficulty bomb deployed at block 15530314 on Sept. 14, 2022, the day before "The Merge" went live. Mining has all but disappeared, most likely because the proof-of-work reward system was removed and ETH cannot be mined anymore.

Understanding the Difficulty Bomb

In the world of cryptocurrency, the term difficulty describes how difficult the computations needed to mine a block in a blockchain for a particular cryptocurrency are. Mining a cryptocurrency is often confused with creating a coin; however, mining is the verification process that involves solving the 64-character hash that encrypts the transaction information. When a miner's machine solves the hash, they are rewarded with a coin.

The original Ethereum blockchain came with an intrinsic feature that increased the difficulty of mining over time—the more blocks that were mined, the more difficult and time-consuming it became to mine the next block.

Ethereum's developers created the difficulty bomb to increase the difficulty of solving the hash exponentially more than before, eventually making it too expensive in time and energy to be worth the cost.

Ethereum's developers always intended to move to proof-of-stake, which is expected to consume 99.95% less energy than proof-of-work.

Ethereum’s difficulty bomb is a deterrent for miners, who may want to fork the original blockchain to continue mining using the PoW mechanism. The primary reason miners won't want to switch to PoS is that the expensive mining machines and farms they have created will become obsolete, at least as far as earning rewards for profits.

Difficulty Bomb Challenges

Migrating to PoS was an enormous challenge for the developers—they had to keep pushing the difficulty bomb release date back because The Merge kept being rescheduled. Releasing the bomb before upgrading to PoS would have been counterproductive—the difficulty bomb would have significantly slowed down transactions and severely congested the network.

There have been six upgrades that, among other fixes, pushed back the difficulty bomb:

  • 2017: Byzantium update
  • 2019: Constantinople update
  • 2020: Muir Glacier update (difficulty bomb only)
  • 2021: London update
  • 2021: Arrow Glacier update (difficulty bomb only)
  • 2022: Gray Glacier (difficulty bomb only)

Is Ethereum Getting Harder to Mine?

Ether (ETH), the native Ethereum blockchain and ecosystem cryptocurrency, can no longer be mined due to the transition from proof-of-work to proof-of-stake consensus.

What Does Ethereum Difficulty Mean?

Ethereum difficulty referred to the increasing amount of time it took to validate transactions under the proof-of-work (PoW) consensus mechanism. The transition to proof-of-stake in September 2022 removed PoW as the consensus mechanism for the Ethereum blockchain, so difficulty is no longer an issue.

What Will Happen to Ethereum Miners After The Merge?

Ether (ETH), Ethereum's native cryptocurrency, can no longer be mined. Miners will need to switch to a minable cryptocurrency if they want to continue mining. Alternatively, they can switch their mining activities to validation activities to earn rewards and help secure the blockchain.

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Article Sources
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  1. Etherscan. "Ethereum Network Difficulty Chart."

  2. Ethereum Improvement Proposals. "EIP-5133: Delaying Difficulty Bomb to mid-September 2022."

  3. Ethereum. "Ethereum Whitepaper: Scalability."

  4. Ethereum Foundation Blog. "Ethereum’s Energy Usage Will Soon Decrease by ~99.95%."

  5. Ethereum Improvement Proposals. "EIP-649: Metropolis Difficulty Bomb Delay and Block Reward Reduction."

  6. Ethereum Improvement Proposals. "EIP-1234: Constantinople Difficulty Bomb Delay and Block Reward Adjustment."

  7. Ethereum Improvement Proposals. "EIP-2384: Muir Glacier Difficulty Bomb Delay."

  8. Ethereum Improvement Proposals. "EIP-3554: Difficulty Bomb Delay to December 2021."

  9. Ethereum Improvement Proposals. "EIP-4345: Difficulty Bomb Delay to June 2022."

  10. Ethereum Foundation. "Gray Glacier Upgrade Announcement."

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