Well bitcoin all together, like in Algeria and Bolivia; its use may be restricted to certain kinds of entities, like financial institutions in China; or it might be totally legal and implemented into the taxation system, like in Israel. Most regulations concerning Bitcoin are not established directly to control Bitcoin itself, but to manage all cryptocurrencies, Bitcoin being one of them. A lot of central financial authorities do not recognize Bitcoin as a currency and regulate it, rather, as an asset, stating that they would not regulate its use, but will warn its citizens of the high risks that come with its usage.