Operation Shrouded Horizon was an 18-month international law enforcement investigation culminating in the July 2015 seizure of Darkode, an online cybercrime forum and black market, and the arrest of several of its members.

The case involved law enforcement agencies from 20 countries, led by the United States Federal Bureau of Investigation (FBI) with the assistance of Europol, in what the FBI called "the largest-ever coordinated law enforcement effort directed at an online cyber criminal forum".

[9] Upon announcing the charges, United States Attorney David J. Hickton called the site "a cyber hornet's nest of criminal hackers" which "represented one of the gravest threats to the integrity of data on computers in the United States".

Though led by the FBI and assisted by Europol, reports credit agencies in 20 countries: Australia, Bosnia and Herzegovina, Brazil, Canada, Colombia, Costa Rica, Cyprus, Croatia, Denmark, Finland, Germany, Israel, Latvia, Macedonia, Nigeria, Romania, Serbia, Sweden, United Kingdom, and United States.

[1][2] Only two weeks after the announcement of the raid, the site reappeared with increased security, employing Bitcoin-based blockchain authentication and operating on the Tor anonymity network.