Oh, I didn't know transaction value was known to transaction block-miners; that seems like a flaw. Assuming there's a bidding system, wouldn't transaction cost tend to zero?
(Seems I need to review bitcoin transaction mining. Suggestions for a good resource on that?)
Yes in a way it's a flaw, or rather a misfeature. Monero solves this by hiding all transaction amounts (and sending/receiving address as well).
The transaction fee isn't set by the amount but the size (a large and small number take the same space). A larger transaction can for example be created by combining many inputs (spending from multiple addresses in a single transaction).
The fee isn't set by miners, but by the user who makes the transaction. If there's competition in the block, which there usually is in Bitoin, then you need to guess a large enough fee and if you get it wrong your transaction can get stuck and not confirm for a while.
Yes, I knew that the transaction value (and source, sink) was known after processing it and putting it in the blockchain, just not that it was known by the miner processing the transaction before putting it on the blockchain - I assumed when "mining" a transaction that somehow the details would be hidden.
Them being visible seems to raise interesting attacks, such as an individual being doxed and then unable to have their transaction verified/accepted.
A sibling comment suggests Monero have addressed this.
Edit: If 51% agree not to process any transactions for accounts holding >$1M worth of Btc can they steal financial value? Like a stock buyback but you pay zero to the holder and get the stock anyway.
> Them being visible seems to raise interesting attacks, such as an individual being doxed and then unable to have their transaction verified/accepted.
You have some fundamental misunderstandings in how bitcoin and bitcoin mining work. I'd suggest reading up on one of the links a sibling comment posted.
In the interim, perhaps you could clear up a couple of questions, as you realise I've not studied the process for maybe 16years (I forget a lot in that time). Are these true?
1) Those processing transactions know which wallet they belong to before they choose to process it (this was the surprise to me presented here).
2) Wallets can be linked to people as the blockchain shows wallet holding value and transactions. (State actors can probably correlate with bank transactions; people in general can learn 'oh John Doe bought pizza from me using that wallet').
> Assuming there's a bidding system, wouldn't transaction cost tend to zero?
Well, that depends. If there is extra space in blocks, then yes the fees tend towards zero (or very low costs, at least, zero is not exactly accurate, even in cases where there is extra block space)
If blocks are "full" and there is more demand for this space, than there is extra space, then they do not tend towards zero, as transactors are bidding on a limited supply of space.
(Seems I need to review bitcoin transaction mining. Suggestions for a good resource on that?)