Tracking voting power

[ppolewicz]

Some smart contracts, such as collateral and treasury, need a way to count votes of validators in order to make a decision for the subnet.
The only metrics currently available are:

• current stake
• stakeweight (stake snapshot saved at the last epoch)

and both can be manipulated with loans and flashloans, where an attacker could hijack the treasury or burn collaterals of his competitors.

The proposed solution is for the chain to provide a reliable metric that the votes could be weighted by. This could then be used by smart contracts as well as on-chain logic.

[sam0x17]

this looks very solid to me. I am personally in favor of min, though I want to better understand how it could be manipulated by whales moving stake between root validators, would min not be the meanest/safest one?

[ppolewicz]

this looks very solid to me. I am personally in favor of min, though I want to better understand how it could be manipulated by whales moving stake between root validators, would min not be the meanest/safest one?

If you were a whale capable of running btcli stake move to shift stake between validators paying tiny fees (a few cents), then I could pay you very little to do just that, weakening the voting power of a validator that you usually stake with. You can do this a many times and it costs almost nothing, which concerns me.

[sam0x17]

based on some additional discussions I think just avg is fine!

[ppolewicz]

It was decided to use stakeweight EMA, meaning it'll only be updated in the epoch block and will range 280 (configurable?) epochs back, so something like new_ema = ( old_ema * 279 + current_stake ) / 280.

Should be indexed by hotkey to not lose power during (accidental or "accidental") deregistration and the validator should be deleted from the map when new_ema < minimum_validator_stake and new_ema < old_ema.