Bitcoin pool GHash.io announced on Wednesday that “it is not aiming to overcome 39.99 [percent] of the overall Bitcoin hashrate.”
This marks a clear departure from the large pool’s recent flirtations with 51 percent. If that threshold is crossed for sustained periods of time, it concentrates power in ways that Bitcoin’s decentralized design normally does not allow.
“If GHash.io approaches the respective border, it will be actively asking miners to take their hardware away from GHash.io and mine on other pools,” the statement continues. “GHash.io will encourage other mining pools to write similar voluntary statements from their sides.”
Cornell professor Emin Gün Sirer, named as an attendee of this meeting, confirmed the document’s authenticity.
As Ars reported previously, once one entity achieves this simple majority, it has powers that circumvent Bitcoin’s normal decentralization. And decentralization is often held up as a salient advantage Bitcoin has over traditional currencies. These 51 percenters, for instance, have the ability to spend the same coins twice, reject competing miners’ transactions, or extort higher fees from people with large holdings. Even worse, a malicious player with a majority holding could wage a denial-of-service attack against the entire Bitcoin network.