You never disclosed a region, so here is information on the second part of your question for the united states.

There is a beautiful post on the /r/personalfinance reddit of just this topic, recommending reading it. It has tons of background information and relevant links to IRS documentation.

https://www.reddit.com/r/personalfinance/comments/7p9a2t/cry...

In terms of the IRS, they are saying this virtual currency is taxable any time you buy, sell, barter, or even mine.