Quote from: Gavin Andresen on January 30, 2012, 05:35:15 PM

But there are other use-cases, like you agreeing to let the government control half the keys, so the government can "guarantee" the transactions, etc. I can imagine the PR campaign: "It is just like Federal Deposit Insurance (FDIC), only for Bitcoin!"

I don't think that will ever happen, though. I know I wouldn't trust the government to keep the keys to my money safe and secure, I don't think most people would, either. More likely is most people will trust banks to hold half the keys, and the governments will then regulate the banks like they do today to get information about who is paying who for what....

Banks are essentially an extension of the government. So, I could see a government placing trust in a bank to keep/manage the government keys since they have control of the banks anyway.

Quote from: BkkCoins on January 30, 2012, 05:03:13 PM

Plausible in the sense that you would accept having a "joint" account with the govt. People don't do that now so it seems unlikely they'd be very willing later. I think the idea was that thru a series of moves the govt convinces people that having a joint account with them for their own protection is a good idea. Personally I can't imagine many people feeling good about having a "joint" account with the govt now or in the future.

You feeling good about it or agreeing to it is irrelevant. Here's the basic way I see this happening:

1) You pay your taxes in bitcoin to whatever government you are a citizen. The bitcoins you use to pay your taxes may be single signature or multisig, it doesn't matter. They will accept any kind of bitcoins whatsoever. In fact, they would prefer you sent them bitcoins that weren't multisig so that they could then "brand" them with their own signature, thereby increasing their influence over the system.

2) You file your taxes and declare how much of a tax return the government owes you.

3) The government generates a multisig transaction containing the number of coins needed to pay your tax return.

4) The government sends you one of the two signatures to that transaction along with an ID card to identify yourself when you want to spend the coins.

5) At this point, you have two options. You can either spend the coins in a government approved transaction, or you can choose to not spend the coins ever. The government doesn't care, because they consider your tax return paid in full, whether you like it or not.

6) If you choose to spend the coins, the government has veto-power over where and how you can spend them. They use this veto-power to ensure that the person receiving the coins accepts them with a multisig transaction in which the government has a signature. If the recipient refuses, the government refuses to let you spend them. In essence, once a bitcoin is "branded", it will forever remain branded regardless of how many transactions it goes through.

This whole process does not require the government to outlaw normal single signature transactions. Nor does it require them to create their own client that prevents normal bitcoin transactions or fork off an entirely new block-chain. All it requires is for them to be patient. Over time, more and more bitcoins would be branded and fall under government control. Eventually, the vast majority of coins would be branded in this way, giving them sway over pretty much the whole network.

Now, there are both benefits and drawbacks to this. You will have to decide whether you think the benefits outweigh the costs. I just thought I should bring it to everyone's attention that multisig transactions open up this possibility.