But unlike other cases where security vulnerabilities have cropped up, Apple may face a higher set of hurdles in ferreting out and repairing the particular iPhone hole that the government hacked.

The challenges start with the lack of information about the method that the law enforcement authorities, with the aid of a third party, used to break into the iPhone of Syed Rizwan Farook, an attacker in the San Bernardino rampage last year. Federal officials have refused to identify the person, or organization, who helped crack the device, and have declined to specify the procedure used to open the iPhone. Apple also cannot obtain the device to reverse-engineer the problem, the way it would in other hacking situations.