Bitcoin is a unique cryptocurrency. Its working and number of coins was fixed at the time of its introduction. Its autonomous and decentralized nature is restricting alterations in bitcoin currency. Bitcoin is getting used in many illegal activities, no one is there to control or regulate it. As a result many countries like China, Japan, Korea, USA, Canada, Indonesia, and Australia are banning/regulating bitcoin from their economy. If bitcoin community fails to take a note of this soon these countries will ban bitcoin completely. Similarly bitcoins functioning needs to be regulated because more and more transaction are remain pending.