The difficulty bomb, if left unaddressed, will slow down the Ethereum network. Developers, on the other hand, believe there will be enough time to deal with it later.
You’re driving down the road steadily when you notice a yellow light. Do you a) rev the engine and try to get through the intersection before the light turns red, or b) stop and wait for the green light?
That is the type of decision that Ethereum core developers will have to make in the much-anticipated transition to proof of stake. In a meeting last Friday, they decided to ignore the impending difficulty bomb, which will make the network more sluggish, for the time being as they raced the engine toward proof of stake. If their timing is off, they might have to come to an abrupt halt.
All of this is taking place while Ethereum users await “The Merge.” That isn’t a scene from a John Carpenter film about symbiotic zombies or Elon Musk’s latest power play.
Rather, The Merge represents Ethereum’s transition from proof of work to proof of stake. Unlike proof of work, which involves “miners” using their computing power to validate transactions in exchange for the chance to earn ETH, proof of stake involves ETH holders locking up a portion of their coins to validate transactions and receiving a portion of the rewards.
It’s part of a larger push, which includes the implementation of “shard chains” and other measures, toward a faster, cheaper, less-congested network known colloquially as Ethereum 2.0.
The difficulty bomb is an element written into Ethereum’s code to incentivize this transition and ensure miners do not refuse to come along after the switch.
The difficulty bomb works by making it more difficult to mine new blocks on the proof-of-work chain, which means miners must work longer to crack the cryptography. The anticipated outcome is that mining will become so time-consuming (and the network will become so slow) that it will become potentially unprofitable.
There is, however, a way to stop it. The bomb was created by developers, and it can be delayed with some effort. They buy themselves more time to build the proof-of-stake network by essentially resetting the clock. This has already been done by Ethereum developers several times, most recently with the Arrow Glacier upgrade in December 2021.
Delaying the difficulty bomb, on the other hand, requires time and energy and may divert resources away from The Merge preparations. While at least one developer on the call stressed that the update itself is “trivial,” getting users to upgrade is not.
Furthermore, there is a psychological impact at work. The ticking time bomb is consuming mental energy, but any distraction from the larger network shift could result in another round of sighs from ETH holders and investors. The Ethereum Foundation pushed back its informal estimated delivery date from Q2 to Q3 of this year in April, and many users are growing impatient for the delivery to arrive.
The preparation work of the developers is currently being tested. Devs created a “shadow fork” of the mainnet in early April, copying Ethereum blockchain data to a testnet to see how the real network would function after the switch. This will be repeated by the developers this week.
Tim Beiko, who leads the Ethereum Foundation’s All Core Devs meetings, argued in Friday’s meeting that it was best to re-evaluate the difficulty bomb in the next meeting on May 13 or even on May 27, noting that the current Ethereum experience was not degraded and would not be for several weeks. He suggested that the best way forward was to keep testing and see where things stand later.
The current average block time is slightly more than 13 seconds. Developers briefly debated how long would be too long for network users to handle, given that each slowdown adds to the congestion. How about twenty seconds? What, thirty seconds? If they get the timing wrong, the network could become as slow as molasses, putting pressure on developers to address the bomb.
But with The Merge so close, even a half-minute delay may not be such a big deal. As Ethereum co-founder Vitalik Buterin stated, “we have to weigh the pain of doing an extra delay hard fork versus the pain of living with 21 or 25 second blocks for a while, which we have done and the world did not end.”
“Ultimately, this is the last time the block time will be anything other than 12 seconds,” he added, sounding optimistic about a future without the difficulty bomb.