CUPERTINO, Ca. – Apple CEO Tim Cook denounced a federal judge’s order to crack open an iPhone used by a terrorist, calling the situation “chilling” and saying it would deal a major setback to online privacy for all.

To hack the phone, CNET.Com reported, the FBI wants Apple to build a new version of its iOS software that Cook claims bypasses the iPhone’s security features and creates “the potential to unlock any iPhone in someone’s physical possession.”

“The US government has asked us for something we simply do not have, and something we consider too dangerous to create,” Cook wrote in an open letter posted on Apple’s website. “They have asked us to build a backdoor to the iPhone.”

On Tuesday, a judge ordered Apple to assist the FBI in unlocking an iPhone linked to December’s terrorist attack in San Bernardino, California. Cook warned that such a version of iOS would create, for the first time, a backdoor into all of Apple’s encrypted devices and would “undermine the very freedoms and liberty our government is meant to protect.”

Cook is willing to challenge the government all the way to the Supreme Court, according to CBS News, citing unnamed sources. Apple may appeal the judge’s ruling as early as next Tuesday, although the timing could slide another week, CBS News has learned. (CBS is the parent company of CNET.) Apple didn’t immediately respond to a request for comment. 

The Apple iPhone story will be one topic discussed Monday on M2 (squared) TechCast by cyber security experts Richard Stiennon and Dan Lohrmann. M2 TechCast, a weekly Internet radio show on the Podcast Detroit Network. You can listen live at 3 pm Monday, or on-demand anytime at http://www.podcastdetroit.com/artist/mi-tech-cast/