Apple is appealing against a $368m (about £240m) award granted to patent holding company VirnetX by a federal court in Texas.
The company gave notice Monday that it was appealing against the judgement of the US District Court for the Eastern District of Texas, Tyler division in the United States Court of Appeals for the Federal Circuit, according to court records.
VirnetX alleged that Apple infringed four US patents in its iPhone, iPad and iPod products. Two of the patents describe a method of transparently creating a virtual private network between a client computer and a target computer, while the other two disclose a secure domain name service, according to court records.
After a jury trial last year, the Texas court ordered in February that Apple pay $368m in damages to VirnetX for its infringement of claims relating to the four patents, besides pre-judgment interest, post-judgment interest, and post-verdict damages.
The court also denied last month a motion by Apple to alter or amend the judgment.
VirnetX filed the patent infringement suit in August 2010 against Apple, Cisco Systems and other companies. On the eve of trial, only Apple and Cisco remained. The court allowed separate trials, setting Apple's trial for 31 October last year.
The Nevada company describes itself as an internet security software and technology company with patented technology for secure communications including 4G LTE security.
"We expected Apple to appeal," said Kendall Larsen, CEO and president of VirnetX, in a statement. The company expects to prevail in the appeal. Apple could not be immediately reached for comment.