Hi @shea256, thanks for your feedback!
We’ve been calling the scenario you just described “free-mining,” whereby a miner who knows their addresses are going to be picked for the next round of PoX rewards has every reason to transfer as much BTC as they possibly can in order to win sortition “for free” (since they’d be getting their BTC back in the overwhelmingly-likely case that they win). There’s a variation of PoX whereby miners are required to burn at least b% of their BTC no matter what, which reduces the problem from mining blocks for free to mining blocks with a maximum discount.
I think your proposal is interesting, but I have a few questions:
I think what you saying is that before the “prepare” phase (where Stackers bless the fork), there’d be a phase where miners put up a STX collateral for each Bitcoin sortition they intend to participate in. If a miner intends to mine a Stacks block in Bitcoin block B, they have to lock up some number of STX that effectively constitutes a promise that at Bitcoin block B, they’ll send a PoX transaction. If they do, they’ll get their STX back. If they don’t, the STX will be burnt. Is my understanding correct?
If this is what you mean by “commit to a given round,” then aren’t the following still true?
- Miners still have a chance of free-mining if their Stacker reward addresses are selected for Bitcoin block B – i.e. a miner can get lucky.
- A STX whale miner can post collateral for every Bitcoin block in the reward period and be guaranteed that they’ll get to free-mine.
I think you’re saying here that miners have to put up an entire STX coinbase as collateral? There’s no way to know in advance how many STX a miner will receive from a block, however, since the miner doesn’t know how much transaction fees they’ll get. Doesn’t this mean that the protocol-dictated collateral is potentially too low, in any case?