Quote from: Qoheleth on January 18, 2014, 09:44:04 AM

Quote from: maaku on January 18, 2014, 09:31:28 AM

You would never sign it.

But how would you know? If only one Wikileaks donation makes it into the final txn, wouldn't each participant just assume it was their donation? How could they tell otherwise?

A possible solution:

Each participant must have all the information from all participants to create the transaction for themselves (i.e. know all inputs and outputs). If both Participant A and Participant B create unique identifiers for their outputs (both for 1BTC, both to address 1HB5XMLmzFVj8ALj6mfBsbifRoD4miY36v, but each with a unique identifier, X and Y, respectively), then when the Controller C specifies the full inputs and outputs to create the Transaction, it will also need to indicate the unique output identifiers.

When Participant A and Participant B create the Transaction from the information from Controller C, they will only create and sign a transaction where Controller C indicates the correct output amount, address, and identifier. Participant A will only sign a transaction that has an output with identifier X and Participant B will only sign a transaction with identifier Y.

Participant A and B then send the correct signatures to the Controller who recreates the same transaction from the inputs and outputs, but now with the signatures of Participant A and B.