The Mischievous Little Solo Beef Block

A few days ago a few of us here noticed that another solo Block had been found.

As a Jedi master that I am, I sensed the block coming and managed to post about it first (#881884), and also named it "Beef Block" as the last four letters of the Block's Hash spell out beef. Furthermore, two other fellow stackers also noticed the block (#882477 and #883059). These extra posts, added with some interesting discussion both under @0xbitcoiner's post and in the Barcelona Bitcoin Only telegram groupchat peaked my interest. Thus, I wanted to write about this mystical little solo beef block.

First of all, this was no regular solo block (not that solo blocks are regular, sadly), as this one wasn't publicly claimed by any solo miners, as is customary. So far we have had a couple of Bitaxe blocks, the Apollo Bit fully self hosted block (own ASIC, own node, own pool) and also the unforgettable Telehash Block by the Bitcoin Park guys (historic moment!).

At first, it just looks like any other CkPool block, as the Coinbase OP_RETURN, (the thing that pools use to signal who mined the block) had a clear "ckpool" written on it.

But when you check out the actual Coinbase OP_RETURN of the solo CK Pool that everyone uses to solo mine (apart from Public Pool .io), you see that these don't match!

The next step is then to explore the outputs.

When the a solo block is found, there is no pool fee to be paid and all the rewards go straight to the miner's wallet. A great example is the Bitcoin Park Telehash block which only has one output and an extra opreturn:

But on the solo CK pool blocks, all solo blocks need to pay a flat 2% fee straight out of the coinbase. The last block found by them is a good example:

It's worth noting that CK pool dev has an on chain footprint going all the way back to 2016, and that he usually uses the same output address for that 2% dev fee. I won't dox him much further, if you want to see that info, put some PoW ;)

Then, what type of outputs does this marvellous little solo beef block follow? And if it has a 2% fee, does it go to the same address as the solo CK pool?

Well, it follows the solo CK pool style of having 2 outputs, one for the miner's address and one with the 2% flat fee to a different address. But the address is definitely not the one used by CK Pool, and he would shortly after confirm on twitter that this block didn't originate from his solo pool.

Well, by the looks of it, this pool payout addresshas also been active since around mid 2014, and most of it's inflows (if not all) come from mining. Over the years, the Address was active recieveing coins and moving them around till around 2020, when it went quiet for almost 4 years.

This is quite interesting, and we can see that this payout address has had coinbases with all sorts of pool related OP_RETURNS. From "Bitfury/BIP100" and "Hashmine .io" to"Kano" and "bebop". But there's always a "ckpool" tag in front of it.

Intriguingly enough, Checksum, co-founder of Bitcoin Mining company Pow.Re, suggested on twitter that it could be a secret pool that we aren't invited to.

Personally, I truly have no clue what it could be, as there seems to be no reason to this madness.

On one end, we have the pool payout being super irregular and happening in bursts. One in 2015-16, with some random blocks till 2020. Then 4 years of silence, and the sudden reappearance, with quite some hashrate (4 blocks in less than a month at the end of 2023, and now 5 blocks in 5 months).

Furthermore, the miner payout addresses keep changing, with some early blocks from the 2014 and 2015 era having 3 payout addresses (Miner, and 2 pools?). And if you follow some of those addresses, they received payments from other blocks that have different OP_RETRUN messages in the coinbases.

Thus, I feel like there's definitely someone doing something in the blockchain, and they've been doing it for a gooood while. More than a Decade now! Perhaps it's some sort of OG big miner using this as his stealth/testing private pool?

Who knows what this masquerading little solo beef block is hidding!

With all of that, I hope you enjoyed it.

May the Hash be with you!