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

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 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)

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