Haha, dude!
They can keep them hidden, but they can't use them to transact with registered (legal) merchants,
Just not with the green addresses of merchants, you mean.
nor can they be used to pay taxes.
Oh dear, yes, that will certainly keep them from using non-green addresses!
Once an unregistered address interacts with a registered merchant address, the police are immediately summoned and the block will not be processed by government miners (they don't need to profit off mining, and can do it as a "public service." Once they adopt Bitcoin as the official currency of Satan/America, they will be able to throw a LOT of cash at this, leaving little incentive for profit-centric entities to mine).
Ha, so Bitcoin would essentially become dependent of governments again? Not gonna happen sir
There will be plenty of private transaction-processing nodes all over the world.
The Bitcoin system cannot be manipulated by single organizations or authorities, not because of any arbitrary rules, but simply by design. They can summon the police all they want. Decentralized P2P traffic is here to stay, whether someone else wants it or not.
When an individual submits his addresses, he testifies that those are the only addresses he controls. It would be likely not be difficult for government to prevent individual-to-individual transactions simply by having enough hashing power to be able to effectively dictate which transactions are processed.
I think you strongly underestimate the hashing power of all individual bitcoin users combined.
And besides, it doesn't matter how much hashing power the government gets. They can deny to confirm transactions all they want. All that matters is that there is enough hashing power delivered by others, to confirm any pending transactions. Governments adding more and more hashing power for themselves, does not in any way decrease the hasing power of others.
(as an aside, citizens should be required to turn in their wallets' private keys when registering their addresses.
Oh, haha, right!
Additionally, there is no reason the government cannot easily implement [or have corporations implement] something which can detect whatever the government wants to call "taint," or have merchants use payment processing software which will not accept funds from addresses not in the database, though it will send an immediate alert to the police.)
There is no reason why any user or merchant would not choose to complete ignore whatever tainting system the government comes up with.
And government-restricted payment processing software? Why would they stick to that. Nothing prevents them from using an alternative system (for their additional, non-registered addresses) on the side.
The government would be able to effectively reverse transactions (if citizens are required to submit private keys). Since funds can't go from merchants to unregistered individuals, petty theft of "cash" would pretty much be eliminated. Even if someone stole the funds to an individual account, they'd immediately be summoning the police, which makes the act much more complicated for the average petty criminal. It may also permit tax reports to be automated given the government knows exactly where everything's going if everyone's registered in a database. Transaction flags could be included which indicate to the IRS supercomputers how to tax the transactions.
Keeps getting better and better
You know what would actually happen? Any addresses with compromised private keys (because they were handed over to the government) will me marked as 'unsafe' and
that is the portion of Bitcoin that will become ignored by the rest of the network. Good luck government & police. Reverse all you want. In the mean time we'll stick to our own subsytem that you don't know about and have no control over whatsoever, thank you very much.