Quote from: mappum on February 07, 2015, 01:06:16 AM

Additionally, a way to solve the malleability attack is to require party A to deposit some coins into party B's initial multisig deposit. If A mutates the transaction, they are also tying up their own funds in the process. This solution is already possible today, I may implement it in the Mercury alpha.

If A has to do that before B puts up any money, then doesn't that give B a chance to blackmail him?

That is, instead of proceeding with the transaction, B says, "Your coins are now inaccessible without my co-operation. You can get half back and give half to me, or get none back. Your choice."

Re: malleability, I think there are still a few parts of BIP62 that aren't implemented yet and there might be sources of malleability still undiscovered. It'll take time to become confident, but it'll happen eventually.