No. that is very impossible. The reason why many people got interested to the bitcoin is because of being decentralized. The government can't control the bitcoin and it can't be taxed.
What is it with the bubble heads in this forum?
In most countries it's taxed right this very minute. They don't care that it's decentralised. They don't care that it's 'on the internet'. They don't care that you took a risk. If you bought it for less than you sold it and it goes over your personal tax allowance then there's some tax.
If you sell enough of your sweaty work out thongs to perverts, that's taxable. If you sell enough finger paintings of Barbra Streisand, it's taxable. They're both far sillier and more abstract than Bitcoin but it's all the same thing.
You're welcome not to pay it. Don't be sad if they turn up at your mansion with a fleet of supercars outside and take it all away and shove you in jail.
There are countries where it isn't taxable. If you live in one then congrats. If you don't then pay some bleedin' attention.
In my country right now I don't consider it taxable for the main time, because the wallet site that I've been using already affiliated with central bank of the country which mainly the site was taxed and license registered. For now the development of the wallet site was still on going for further improvement which most of us doesn't know when will it will be taxed fully with all transaction including withdrawals. If that will happened I don't think that the demand of bitcoin will be like this what we are experiencing right now, it maybe changed and it may caused sudden drop of bitcoin economy; so the freedom of currency will be removed by that time of imposed bills on it.