Many large mining pools aren’t actually independent, but seem to be proxies for AntPool, according to Casey Rodarmor.

Bitcoin Ordinals creator Casey Rodarmor took aim at the state of decentralization in the Bitcoin mining space.

“Bitcoin’s entire value proposition rests of censorship-resistance, which can only be guaranteed by decentralized miners competing to produce blocks,” said Rodarmor in a post on X. 

“The current state of Bitcoin mining decentralization is, unfortunately, not great. Many large pools which were previously thought to be independent now seem to be mere proxies for AntPool, with the same transaction selection policies.”

Looking at the merkle branches that mining pools send to miners as part of stratum jobs, it’s clear that the BTCcom pool, Binance pool, Poolin, EMCD, Rawpool, and possibly Braiins* have exactly the same template and custom transaction prioritization as AntPool. https://t.co/KTjFWtTXEP pic.twitter.com/xhCrdvkOH8

— 0xB10C (@0xB10C) April 17, 2024

An X post from pseudonymous Bitcoin developer 0xB10C shows that mining pools run by BTC.com, Binance, Poolin, EMCD, Rawpool, and possibly Braiins have the same custom transaction template as Antpool.

“I’ve heard speculation about this all being liked to an FPPS partnership with AntPool/Bitmain,” said the developer.

“Essentially a pool of pools and a lot of mining centralization.” 

These revelations are particularly concerning, when looking at the hashrate break up amongst all Bitcoin mining pools. Data from Blockchain.com shows that just two mining pools — Antpool and Foundry — were responsible for mining the majority of Bitcoin blocks over the last year.

One solution to this problem, in Rodarmor’s view, is the Stratum V2 mining pool, which allows miners and not the pools they mine for to dictate which transactions are included in each block. 

Stratum was developed by Braiins Pool in collaboration with Bitcoin core developer Matt Corallo, with the goal of improving efficiency and preventing man-in-the-middle attacks. 

Speaking to TFTC earlier this week, Corallo said that as long as large single entities are responsible for mining Bitcoin, we’re setting ourselves up for trouble.