The first criminal copyright sentence has been given to the operator of a "cyberlocker" site.

The operator of a major music piracy site has been sentenced to three years in prison.

Rocky Ouprasith, now 23, was the man behind RockDizMusic.com and RockDizFile.com. The latter was the second-largest online file-sharing site specialising in pirated music in the United States in 2013, according to the Recording Industry Association of America.

Federal law enforcement shut down the sites in October 2014, and Ouprasith pleaded guilty to one count of criminal copyright infringement in August. In addition to a 36-month prison term, he will also get two years of supervised release, forfeit over US$50,000 and pay nearly US$50,000 in restitution.

As part of his guilty plea, Ouprasith admitted that he obtained digital copies of copyrighted songs and albums online and encouraged others to do the same, then used the music files to populate overseas servers.

Visitors could download music via hyperlinks on his sites, according to court documents, and Ouprasith made money through online advertising agreements and by selling premium subscriptions offering faster downloads.

He also admitted to ignoring complaints or merely pretending to remove content when copyright holders complained in some cases.

Ouprasith didn't appear to do much to hide his association with the sites. According to a statement of facts connected to his plea agreement, he listed himself as the owner of RockDizMusic.com on his LinkedIn page and conducted business through a company called RPO Productions.

Ouprasith's case appears to be the nation's first criminal copyright sentence handed out to the operator of a "cyberlocker" site, which uses cloud storage to host pirated material.

However, the United States has been pursuing other cases.

Perhaps most notably, the US government is seeking to extradite Kim Dotcom, the onetime operator of file storage site Megaupload who faces copyright-related charges, from New Zealand.