The legality of Bitcoin is a contentious issue for law enforcement and law enforcement, as they are targeted at the digital currency in an attempt to control its use. Bitcoin is still at the initial stage of development, and many legal bodies are trying to resolve the crypto currency, not to mention the adoption of laws around it.
It remains a confidential thing about it and we really don't know how the law enforcement could control bitcoin's legality. The initial development is our future towards price to gain at better value, and for now there's no certain approved rules that bitcoin was totally covered of. Nor legal nor illegal, bitcoin is always a decentralized body which was separated from centralized fiat currency.