I think you are looking for an arbitration service.
Upon rereading my question, I can see that the majority of it is off-topic for this forum. Pardon me please; I appreciate your patience in this regard. Thank you also for the reference.
Do you have any insight toward the remaining three questions:
- If the seller acts as the organizer, creating a 2x3 LockBox with a two-wallet combination under his own control, does the buyer retain his protections?
- Once the buyer commits funds to the LockBox, can they be extracted without separate permission from each party?
- If the transaction is split, with final remittance occurring after a year, what backup measures should each party take in the meantime?
Thanks,
Jeff Bowman
Fairbanks, Alaska
1) Why would the buyer have protection? This is the same as giving the seller full control of the funds. The scheme you are thinking of is a 2-of-3 with one key to the seller, one to the buyer and one to an arbitrating 3rd party. The buyer and the seller have to cooperate for the funds to go anywhere. If they fail to find an understanding, then the 3rd party can come in and act as a judge, and has enough power to sign the coins off to the party he declares rightful in its demands.
2) Depends on the scheme again. M-of-N lockbox with M keys to any party is the same as giving full control of the funds to that party. If you want the 2 parties to have same power over the coins without the ability to wrong the other, each party has to have an amount K of keys, where K < M and 2*K >= M, and the 3rd party needs to have an amount of S of keys, where S < M and S+K >= M
3) The nature of the transaction doesn't change. Part of the due sum is paid in advance, the rest at delivery, kept in the 2-of-3 escrow. This concept doesn't mix well with 2-of-3 escrow however. The idea of paying a part of the price in advance is to mitigate the risk to the seller while keeping the risk to the buyer lower than if he just paid upfront.
2-of-3 escrow bypasses that entirely. With a 3rd party judge, buyer and seller have to agree for the funds to go anywhere. In case they disagree, the judge comes in. So the buyer puts full payment in escrow upfront, in the 2-of-3, at which point the seller starts on his work. The buyer then signs his half of the lockbox when the product is delivered, to the expected specs.
If the seller needs some money upfront to start on development, then that's part of another agreement, usually some sort of non refundable pre-order clause.
If you want to give even more protection to the buyer, you can use a simulfund to get the seller to put some funds in escrow at the same time the buyer puts in the full price of his purchase + extra, to cover litigation fees and pay for the 3rd party's time.
If the whole thing goes smooth, the 3rd party won't be involved beyond providing his public key once, so he could be entitled to small fee for his small burden. If there is a dispute between buyer and seller, the 3rd party has to kick in and review both sides' evidence. As he comes to a conclusion, he will then release the fees to the party he deems righteous, and pocket in the fees for his work from the guilty party.
This keeps the 3rd party motivated to review the case if needs be, and gets the seller involved more in the transaction: if he walks away, neglects this job, or takes something juicer on the way and doesn't try to release the buyer's funds asap now that he failed on his obligations, then it will cost him the litigation funds.
The flaw in this basic model is if the 3rd party colludes with one of the other parties to steal the funds, so you have to find a trustworthy individual to act as escrow. However this method is a lot better than just letting the buyer deal with the seller, and better than 1-of-1 escrow where the 3rd party holds all the funds and may run with them at any point in time, and usually commands a hefty fee whether the transaction is successful or not, in the case he is trustworthy, since you have to trust him a lot more, and he has a lot more work to do, regardless of the outcome.
If you walk out of that model, you'll most likely end up giving one of the parties too much power over the other one. I'm not saying it can't be done, but you're gonna have to get creative, and I don't thing multisig is the sole technological answer to that one.