Thanks for your answer, gmaxwell.
So, if I understand correctly, what you propose in your "I taint rich" thread is:
- You say publicly that someone make a transaction with this schema (first transmission):
inputs:
a) His address (spendable previous output with X BTC)
b) Your address (spendable previous output with 1 BTC)
outputs:
a) A different address of him (X BTC)
b) You address (with 1 BTC)
- This transaction is signed and sent back to you (cited: "via PM, anonymous gpg encrypted email, or a post in this thread") (second transmission).
- You sign this transaction and announce it (third transmission)
Or, in other words, in order to agree on the outputs, we need to have a rdv server (either an IRC server, a Forum -as in your thread-, a P2P network, etc.). We cannot avoid playing ping-pong with the transactions (I have nothing against it. In fact I proposed a detailed specification some post above).
For SIGHASH_ALL these can be accomplished by simply agreeing on the outputs before any signing begins.
How can we agree on something without previous communication? What is the advantage over, for example, sending back and forth the transaction?