A US judge has issued the longest-ever sentence for software piracy - 87 months in prison.

Californian Nathan Peterson also forfeited nearly all of his assets to the Virginia court, agreeing to pay more than $5.4 million in restitution. He pled guilty to two counts of criminal copyright infringement in December.

The US Department of Justice (DoJ) called Peterson's website, Backups.net "the largest for-profit software piracy site ever shut down by law enforcement." The site illegally sold software that would have been worth $20 million on the retail market, the DoJ said.

Judge T.S. Ellis III ordered that Peterson begin paying off the remaining $5 million in damages in monthly installments 60 days after his release from prison.

In criminal piracy cases, the average damages resulting from pirated software are just over $9 million, or less than half of the $20 million caused by iBackups, according to the Software & Information Industry Association (SIIA). The $5.4 million Peterson agreed to pay in restitution is eight times the average fine of $659,000.

Peterson's site used Google text ads to find customers.