When Silk Road was shut down by the FBI in 2013, drug enforcement authorities probably hoped that would be the end of it, but a new study by Rand Europe suggests the opposite has happened.
The study's authors conclude that in the three years that have passed since the original Silk Road was closed, drug sales on the dark web have tripled, with the number of listings for drugs five-and-a-half times higher than before.
The cryptomarkets, which use currencies like Bitcoin, have appeared and disappeared since Silk Road's closure, but the study found 50 live markets, with three of those including 65% of all listings, whether they be for drugs, alcohol, tobacco or other illegal goods and services.
The research suggests that only 18% of dark web drug transactions consist of sales for personal use, determined as sales of $100 (£77) or less, while the authors say "it is likely that many cryptomarket customers are drug dealers sourcing stock intended for offline distribution".
Cannabis still remains the most popular drug bought online, accounting for 31% of all drug revenues, while stimulants including cocaine, ecstasy-type drugs including MDMA and psychedelics and opioids help make up 70% of all revenues on cryptomarkets included in the study.
The growth in use is attributed to perceived safety, variety, quality, ease and speed of delivery, while the authors go on to conclude that despite law enforcement in Western European countries, particularly the Netherlands, having an impact on the confidence in cryptomarkets, "the size of trade has grown nonetheless".