Similarly besides its high value, the anonymous and untraceable nature of Bitcoin transactions makes it such a perfect currency for criminals. Bitcoin has attracted considerable adoption by criminal dealers on dark marketplaces using it as a convenient medium of exchange. From drug gangs in Spain, money launderers in the US, cyber-crime gangs in Russia to kidnappers in Turkey; all have found motivation and convenience in using Bitcoin and other cryptocurrencies to complete their underworld transactions unnoticed.