Software company Autodesk can stop a man from re-selling second-hand copies of its software because the programs are licensed to users, not owned by them, a US appeals court has ruled.

Software producers who clearly impose restrictions on buyers and make it clear that buyers are only licensing material rather than buying it outright do have the right to restrict second hand sales of the material, the US Court of Appeals for the Ninth Circuit has said.

Autodesk is involved in a long-running legal dispute with Timothy Vernor, who sells goods on auction site eBay. He bought second hand versions of Autodesk's architectural drawing software from a company and made them available for sale on eBay, but Autodesk made repeated claims that this infringed its copyright.

Vernor's eBay account was eventually suspended, leading him to take a case to the courts, asking a judge to declare his activity lawful.

A US District Court agreed with Vernor, saying that a previous case involving film prints lent to actress Vanessa Redgrave, the Wise case, set a precedent that transferred material could be owned by the person to whom it was given.

The Court of Appeals disagreed, and said that the Wise case did not mean, as the lower court had said, that any agreement which allows a person to keep a copy of copyrighted material was a sale rather than a transfer of a licence.