> I don't think partially-signed transactions belong on the main Bitcoin > P2P network, mostly because I don't see any way of preventing somebody > from endlessly spamming bogus, will-never-be-completed partial > transactions just to be annoying.
... of course I write that and then start thinking about ways you COULD use the P2P network to distribute signatures, maybe by broadcasting (and paying fees for) complete transactions that contain extra signatures for the transaction that you want to sign. Here's a half-baked idea that might be brilliant or stupid: + Start with an escrow transaction, with 3 public keys. I own one of the keys. + I broadcast a 'fee-only' transaction that pays 0 bitcoins to the key I own. But I add extra data to the scriptSig; something like: scriptSig: <escrow_signature> <serialized_escrow_transaction> <sig> <pubkey> scriptPubKey: ...standard DUP HASH160 <pubkeyhash> ...etc nValue: 0 The other parties to the escrow transaction could monitor the block-chain for transactions to my <pubkeyhash>, and get the signature and proposed "spend the funds in escrow" transaction from the scriptSig. ....... "But won't that gunk up the block chain with more data?" Yup. But the parties to the transaction will have to pay for the extra data they're including. And everything in the scriptSigs can, theoretically, be forgotten (or never sent) to most nodes on the network once the transaction is spent and is buried deep enough in the block chain. (a nValue=0 transaction can be considered 'immediately spent'). "Can you really put arbitrary stuff in the scriptSig?" Yup. The IsStandard() check today allows up to 200 bytes, which wouldn't be enough for an extra signature and <serialized transaction>. The standard <sig> <pubkey> is about 150 bytes; part of the multi-signature proposal will be increasing that to 500 bytes to accomodate 3-signatures transactions. A simple 1-input-1-output <serialized transaction> would be around 50 bytes or so. "Wouldn't it be cheaper/better to NOT use the block chain to distribute signatures?" Yup. The only advantage I see is it might be more anonymous to use the blockchain instead of directly connecting to, and finding out the IP address of, the parties involved in the transaction. -- -- Gavin Andresen ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
