I wouldn't use multi-sig for this at all. Instead I would use SIGHASH_ALL | SIGHASH_ANYONECANPAY.
Essentially, Alice creates a transaction which contains her 0.1 mBTC input and a 0.2 mBTC output to the society. She signs it with SIGHASH_ALL | SIGHASH_ANYONECANPAY. This signs her input and the output (meaning they cannot be changed), but allows the addition of further inputs (but not further outputs). She then passes this transaction to Bob. Bob cannot broadcast it as it stands, because the outputs are higher than the inputs and so it is invalid. However, Bob can then add his own 0.1 mBTC input to the transaction, which would make it valid, and can then be broadcast.
Alternatively, Alice could sign with SIGHASH_SINGLE | SIGHASH_ANYONECANPAY, allowing Bob to add his own input as well as additional outputs, in case he doesn't have a 0.1 mBTC ready to go and needs to add a change address.
Topic: Multi-User transaction with Bitcoin. - page 2. (Read 462 times)
Standard 2 of 2 multisig is already a thing but isn't implemented. The lightning network has a similar thing with channels whereby a multisig address is paid but that transaction isn't broadcast until a withdrawal transaction is made so both parties can get their funds back.
Which are you expecting to implement (should the user have the ability to withdraw from the "contract"/multisig)?
Which are you expecting to implement (should the user have the ability to withdraw from the "contract"/multisig)?
In my application I have this idea for a some large number of people who don't completely trust each other, endevor to buy something collectively, like a plot of land that would get subdivided into lots for themselves.
Each of the users make a payment to the society (a n of n multisignature wallet) and in the end payments are made out of it for purchase of the common property land and then implementation of services.
The most simple non-trivial case is a 2 of 2. Let's make up two users Alice and Bob. Can I create a payment transaction from both Alice and Bob, so that both of them pay 0.1 mBTC for the society payment but if unless both sign (pay) then neither pays into it? Is there a wallet that does this kind of thing already?
I think this could be a good way to prevent people from running away with funds. I think the upper limit for n is 15 in Bitcoin. I have a copy of the private keys for some test wallets. Send me a private message if you wish to participate in trying to do this. We should only use popular clients like Electrum, core or Armory. I don't think I should be writing custom wallet software!
Perhaps this can be done with the CSV import mechanism in Electrum. Maybe there is something we can use from the RPC of one of these clients.
Each of the users make a payment to the society (a n of n multisignature wallet) and in the end payments are made out of it for purchase of the common property land and then implementation of services.
The most simple non-trivial case is a 2 of 2. Let's make up two users Alice and Bob. Can I create a payment transaction from both Alice and Bob, so that both of them pay 0.1 mBTC for the society payment but if unless both sign (pay) then neither pays into it? Is there a wallet that does this kind of thing already?
I think this could be a good way to prevent people from running away with funds. I think the upper limit for n is 15 in Bitcoin. I have a copy of the private keys for some test wallets. Send me a private message if you wish to participate in trying to do this. We should only use popular clients like Electrum, core or Armory. I don't think I should be writing custom wallet software!
Perhaps this can be done with the CSV import mechanism in Electrum. Maybe there is something we can use from the RPC of one of these clients.
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