Australian researchers have estimated that 25% of all bitcoin users and 44% of all bitcoin transactions are associated with illegal activity as of April 2017. There were an estimated 24 million bitcoin users primarily using bitcoin for illegal activity. They held $8 billion worth of bitcoin, and made 36 million transactions valued at $72 billion.
In popular cultureLiteratureIn Charles Stross' 2013 science fiction novel, Neptune's Brood, the universal interstellarpayment system is known as "bitcoin" and operates using cryptography.Stross later blogged that the reference was intentional, saying "I wrote Neptune's Brood in 2011. Bitcoin was obscure back then, and I figured had just enough name recognition to be a useful term for an interstellar currency: it'd clue people in that it was a networked digital currency."FilmThe 2014 documentary The Rise and Rise of Bitcoinportrays the diversity of motives behind the use of bitcoin by interviewing peoplewho use it. These include a computer programmer and a drug dealer.The 2016 documentary Banking on Bitcoinis an introduction to the beginnings of bitcoin and the ideas behind cryptocurrency today.AcademiaIn September 2015, the establishment of the peer-reviewedacademic journalLedger(ISSN2379-5980) was announced. It covers studies of cryptocurrencies and related technologies, and is published by the University of Pittsburgh.Thejournal encourages authors to digitally signa file hashof submitted papers, which will then be timestampedinto the bitcoin blockchain. Authors are also asked to include a personal bitcoin address in the first page of their papers.See alsoAlternative currencyBase58Crypto-anarchismList of bitcoin companies