Worries relating to the security of the Tor network have prompted Agora to shut down temporarily.
Launched in 2013, Agora is a marketplace only accessible through the Tor network which can be used to anonymously purchase products through the virtual currency Bitcoin. The market is one of the largest currently online, and as a hidden service, is used to purchase all manner of items including weaponry, drugs, stolen credit card details and electronics.
However, recent security concerns have prompted Agora controllers to temporarily suspend operations.
According to a message sent to Agora users by administrators, posted on Reddit, taking the market offline is only a temporary consequence of the security issue. The message states:
"Recently research had come that shed some light on vulnerabilities in Tor Hidden Services protocol which could help to deanonymize server locations.
Most of the new and previously known methods do require substantial resources to be executed, but the new research shows that the amount of resources could be much lower than expected, and in our case we do believe we have interested parties who possess such resources."
While Agora has not specifically labelled the Tor network vulnerabilities administrators are concerned about, it appears that an MIT research paper documenting ways to de-anonymize Tor users may be the root cause. In July, MIT researchers said a technique called "circuit fingerprinting" could be used to unmask Tor users with a high degree of accuracy.
The Agora team says they have a solution ready to be rolled out which will plug the security hole, but this will take massive changes to their software stack as well as a fair amount of time to implement.
In addition, "suspicious activity" has been detected around Agora servers, prompting a move to a fresh location -- which is only a temporary solution to the overall problem of keeping users anonymous and safe.
"At this point, while we don't have a solution ready it would be unsafe to keep our users using the service, since they would be in jeopardy. Thus, and to our great sadness we have to take the market offline for a while, until we can develop a better solution. This is the best course of action for everyone involved," the team says.
Agora plans to clear as many outstanding orders as possible and has asked users to withdraw their funds, make sure they do not send any Bitcoin to Agora deposit addresses and to expect a delay due to the vast amount of payouts which will need to be processed in rapid time.
However, no definitive date has been issued regarding when Agora will go offline.
A market of similar size and reputation, Silk Road, was closed down by the FBI in 2013.
Read on: Top picks
- How to access Wi-Fi anonymously from miles away
- Apple OS X zero-day flaw hands over root access without system passwords
- Getting physical: A $10 device to clone RFID access keys on the go
- Amazon dreams of drones-only airspace
- Strike the source: RIAA targets BitTorrent protocol to block pirate content
- Three top tips to keep connected cars safe from hackers