Bitcoins have both advantages and disadvantages .The feature of being anonymous which is attracted by many bitcoin users is the feature that is also attracted by many criminals. Recently , ransoms in millions were taken from the movie producers of The pirates of carribbiean and Game of thrones. All these activities has led to the increase in criminal activities associated with bitcoins. Bitcoins is also being used by many spammers who flood the internet with spams and make a fool of investors. Many people have lost their money to spammers and there is no way to indentify them as their identity is hidden as per bitcoin property. So these reasons have fueled the criminal activities associated with bitcoins.