The blackmarket running on the bitcoin block chain for leaking confidential secrets, hollywood movies, software exploits and so on. — by Zozan Cudi (@ZozanCudi) Cryptocurrencies existed for ages but all had the same issue that is common in the world of information technology: the double-spending problem. Bitcoin, introduced in 2009, solved this issue thanks to the block chain technology. The block chain is a massive distributed data base all over…