2-of-3 Transactions

[No_2]

Can anyone experienced at 2-of-3 transactions tell me if the following is correct. And if not why not.

For a 2-of-3 transaction the following is always true:

    • Three parties are required for a 2-of-3 transaction: sender, receiver and escrow.
    • All parties involved in the transaction can verify that the address belongs to the transaction they're participating in, and not one made up or taken from a party's own personal wallet.
    • All parties can view the funds in the destination address.
    • Escrow requests must be signed first or second by the escrow in the chain of events.
    • Escrow is able to grant access to the funds to sender or receiver.
    • Escrow is unable to access the funds themselves.
    • Sender and receiver can still cooperate so that one party receives the funds without the need to rely on the escrow.

[leijurv]

Yes, that's mostly true.
Although, in the second one, you're not really sending it to an "address", you're putting the tx out into a script which would require 2 out 3 signatures from predefined public keys (You can't do this in the main bitcoin client). For that to be spent, either the sender and receiver, or receiver and escrow, or sender and escrow must agree.

[tuheeden]

All,

I see in 2011 here in the forums where escrow was more actively discussed, but I cannot locate any 'real' documentation on how to accomplish this using Bitcoin today.

From this post, clearly it is possible but it looks to be a bit mysterious.

The reason for me asking is: I am reviewing Satoshi's white paper and of course he indicates that 'routine escrow mechanisms could easily be implemented to protect buyers'. If this is technically already coded, then all that is necessary is to make it 'easy'.

Any help would be appreciated.

Thx

[jgarzik]

See http://bitcoin.stackexchange.com/questions/3718/what-are-multi-signature-transactions and links within.

[jdbtracker]

I'm pretty new to this, but on one of the p2p exchange threads I thought this would be a great idea.

but it would be two transactions with 2 out of the three parties acting as escrow.

so A wants to sell their bitcoins
    B is the escrow that accepts the risks they accept A's BTC
    C is the person who is going to get BTC from B act as intermediary escrow and send a wire to A

It's two transactions

C sends the cash to A and authorizes A's BTC transaction to B
A authorizes the BTC transaction from B to C to complete the loop.

A has already transferred their BTC, B has sent their money and won't get their BTC until A gets the cash to authorize the escrow.

the two original parties are holding the triggers on each other and both have lost control of their money.

what do you think, yes I know the escrow assumes a lot of the risk, but that is why they charge a fee to offset any possible probabilistic losses, but the risk is low if a reputation system can be implemented. and yeah creating a three way p2p exchange still require the relevant p2p component to match local btc holders with local btc buyers and escrow intermediaries still need to be made and this system makes it a whole lot harder to match.