Okay lets assume that you do mean about direct taxation on bitcoin then this thing is impossible since bitcoin cant really be taxed directly since its a decentralized thing this is why government doesnt really like it since they cant able to control it but when we do talk on indirect way of taxation then this time is possible where they would really regulate those things which do involve into bitcoin business like on exchanges which they would really imposed taxes but well depending on a certain country on where those exchangers located.