“I’M WAITING for my man / Twenty-six dollars in my hand / Up to Lexington, 125 / Feeling sick and dirty, more dead than alive.” So sang Lou Reed in 1967, about visiting Harlem to buy heroin. Getting hold of drugs has never been all that easy. Scoring has long meant hanging around scary street corners or dealing with thuggish bouncers at nightclubs, with a high chance of being beaten up or arrested. And if you are successful in buying something, the product may not be what you think it is. Heroin is “stamped on” with baking soda; cocaine is cut with extras such as cattle deworming tablets; ecstasy pills may well turn out to be something more dangerous. Imagine, then, if there were an Amazon.com for drugs. That, roughly, is what the Silk Road, a mail-order drugs service hidden in the dark parts of the internet, tries to be. How does it work? The Silk Road is, put simply, an online marketplace, located on a website hidden away from ordinary internet browsers. To access it, buyers must use Tor, software which anonymises internet connections by bouncing data around the globe, encrypting and re-encrypting it en route, until its original source can no longer be traced. Tor’s creation was originally sponsored by the United States Naval Research Laboratory, and it is used by political activists around the world to send messages. But it also allows dealers in drugs and other illegal products to meet online without leaving any trace of their identity. Because it is almost impossible to locate the servers where the website is hosted, it is extremely difficult to take down, in spite of calls from politicians such as Charles Schumer, a New York senator, for the site to be closed.

That still leaves the problem of arranging payment and delivery, however. The former is solved by another piece of cryptographic technology: Bitcoin. Because Bitcoin payments are, much like communications on Tor, extremely difficult to trace, they are ideal for online drug-deals. On the Silk Road, payment works through an escrow service. Buyers move their Bitcoins into the Silk Road’s system and send a message to the seller, containing a shipping address (which is deleted automatically from the system after it is seen—a little like more benign services such as SnapChat). The money is frozen and the dealer sends the drugs, typically by post. When the package arrives, the buyer confirms delivery online and the Bitcoin is released to the dealer. If a package goes missing, the funds remain frozen until an agreement is reached between buyer and seller. Most dealers offer partial refunds for missing packages. To minimise losses, drugs are often hidden inside birthday cards or in packets of sweets. Once they have recovered from the effects, buyers can leave feedback, which helps provide an indication of quality. The Silk Road, which is run by a secretive character known only as “Dread Pirate Roberts”, takes 10% of each transaction. In July 2012 its revenues were estimated to be around $22m per year.

The service is not risk-free. Shipping large quantities of drugs to yourself is unwise: several Silk Road buyers have been arrested, usually after ordering particularly large quantities of drugs online (they include several street-level dealers, who were using the Silk Road as a wholesale supplier). Buying Bitcoin is also difficult in many places because banks restrict transfers to Bitcoin exchanges. What's more, the currency's value can change dramatically before a buyer gets to spend it. Many drug users cannot wait two or three days for delivery of their next hit. But it is all a lot easier than waiting for the man. The police may not agree. Still, there is probably less chance of a drug deal on the Silk Road turning into a murder scene, and customer reviews may be a better guide to quality—and so the risk of overdose and death—than a street-corner salesman’s patter. Buying a line online has never been easier.