Re: [Bitcoin-development] merged mining hashcash & bitcoin (Re: Coinbase TxOut Hashcash)

[Jeff Garzik <jgarzik@exmulti.com>]

On Mon, May 13, 2013 at 5:12 PM, Adam Back <adam@cypherspace.org> wrote:
> When you said destroy-via-miner-fee:
>
>
>> Don't forget:  4. destroy-via-miner-fee, which is useful because it
>> provides funding for a public service (bitcoin transaction
>> verification).
>
>
> Is that directly possible?  Because the reward transaction has no source,
> and no fee?  Or can you put a 25BTC fee in the reward transaction in the
> coinbase?

When a transaction's input value exceeds its output value, the
remainder is the transaction fee.  The miner's reward for processing
transactions is the 25 BTC initial currency distribution + the sum of
all per-transaction fees.  A destroy-by-miner fee transaction is a
normal bitcoin transaction sent by any user, that might look like

Input 1: 1.0 BTC
Output 1: 0.5 BTC

(the miner fee is implicitly 0.5 BTC, paid to whomever mines the
transaction into a block)

Sadly the bitcoin protocol prevents zero-output,
give-it-all-to-the-miner transactions.

-- 
Jeff Garzik
exMULTI, Inc.
jgarzik@exmulti.com