WASHINGTON—Apple Inc. CEO Tim Cook says his company will fight a federal magistrate’s order to help the FBI hack into an encrypted iPhone belonging to one of the San Bernardino, California shooters. The company said that could potentially undermine encryption for millions of other users.
Cook’s response, posted early Wednesday on the company’s website, set the stage for a legal fight between the federal government and Silicon Valley with broad implications for conflicts over digital privacy and national security.

Apple CEO Tim Cook speaks on stage before a new product introduction in Cupertino, Calif. AP Photo/Marcio Jose Sanchez