Grin Cryptocurrency to Discuss Change to Mining Difficulty Schedule

Grin developers are discussing potential changes to the privacy-oriented cryptocurrency's difficulty schedule.

AccessTimeIconMar 26, 2019 at 10:47 p.m. UTC
Updated Sep 13, 2021 at 9:01 a.m. UTC
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The open-source developers behind the privacy-oriented cryptocurrency Grin are discussing potential changes to the project's mining difficulty schedule.

Specifically, those developing the code for the project are looking to potentially adjust what goes into an upcoming Grin hard fork. However, the effects of this possible adjustment would not be seen until 2021.

Prominent Grin developer John Tromp, who invented the proof-of-work mining algorithm "Cuckoo Cycle," suggested changes to what will go into the next hard fork currently set for mid-July during a bi-weekly Grin Governance meeting Tuesday. He also proposed that the matter be put to a vote during the next Grin Governance meeting in two week's time.

Tromp argued in conversation with other developers:

“The announcement of single chip ASICs for [Cuckatoo-31] has undermined our phase out schedule... which looks like it won’t be able to serve its original intended purpose of thwarting single chip ASICs in the foreseeable future.”

Stepping back, ASICs are expensive, specialized hardware devices designed to optimize earnings for a specific mining algorithm. Developers think it's bad that ASICs have come to dominate many cryptocurrencies since they view manufacturers as a centralizing force in what's supposed to be a more open competition.

When Grin started off, its developers aimed to prevent ASIC manufacturers from gaining an advantage over others on the network, attempting to promote healthy competition with manufacturers of GPUs, which are less expensive to purchase and run. To keep ASICs at bay, Grin developers agreed to hard fork the network every six months and tweak the mining algorithm slightly for a period of two years.

As such, developers agreed that over time the network would gradually transition to an explicitly “ASIC-friendly” variant of Tromp's Cuckoo Cycle called "Cuckatoo31+." This would give ample time for many ASIC manufacturers to optimize for this algorithm and hopefully ensure a broad network of miners.

But this might not be going as planned. At present, roughly 81 percent of Grin blocks are being mined using the ASIC-resistant variant of Tromp’s Cuckoo Cycle called "Cuckaroo29." The other 19 percent of blocks are mined using Cuckatoo31+, according to Grin ASIC manufacturer Obelisk CEO David Vorick.

In a phase referred to in Tromp's statements today as the "Cuckatoo-31," this ratio continues to gradually decline. As developer Daniel Lehnberg estimates in today's meeting, Cuckatoo-31 is expected to end August 19 of next year. The following phase – Cuckatoo-32 – will result in a total of 55 percent of Grin blocks mined using Cuckatoo31+. Thereafter, the beginning of Cuckatoo-33 in 2023 marks the phase transitioning to a fully Cuckatoo31+ mined Grin network.

However, this current schedule might lead to problems. Both Tromp and Vorick argue that the present schedule needs to be delayed. If not, Vorick maintains that “it will almost guarantee there will be an [ASIC] monopoly at [Cuckatoo-32],” which is exactly what the Grin developers were trying to prevent.

Vorick told CoinDesk:

“We’ve demonstrated with our single-chip [Cuckatoo-31] miner that multi-chip designs are not competitive, and if the phase-out is not delayed, we will be producing a [Cuckatoo-32] single-chip design as well.”

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This Cuckatoo-32 design “will be expensive and difficult [to build] and will make competing very difficult," Vorick adds.

“We believe that the mining ecosystem for Grin would be better if it stayed at [Cuckatoo-31], where costs are lower and it's easier for new competitors to get involved,” said Vorick to CoinDesk.

In light of this information, Tromp proposes:

“Any change to [Cuckatoo31+] cannot take effect until at least 18 months into the future, unless agreed upon by all affected parties.”

“I’m proposing to proceed with more caution, to take a wait and see approach,” said Tromp. “But also to keep our commitment for the next 18 months as ASIC manufacturers must be able to rely on that for investment decisions.”

Writing on a public Grin forum, Vorick shared his concerns about the phased hard fork roadmap. He explained that while other mining hardware manufacturers "are not upfront about the nature of their hardware," his motivation for disclosing the matter came down to Obelisk wanting "give the community all the information it needs to make informed decisions."

"We really would like to see Grin [succeed] and we would like to do so by collaborating with the Grin community and letting them know what's going on before it happens," wrote Vorick. "We're looking forward to your thoughts and discussion."

Grin image via CoinDesk archives

Correction: A previous version of this report suggested a potential change to Grin's phaseout schedule would impact the project's schedule of hard forks. The article has been corrected to reflect that the potential change would only affect what goes into one of the hard forks.


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