WASHINGTON — Devoted customers of Apple products these days worry about whether the new iPhone 6 will bend in their jean pockets. The National Security Agency and the nation’s law enforcement agencies have a different concern: that the smartphone is the first of a post-Snowden generation of equipment that will disrupt their investigative abilities.

The phone encrypts emails, photos and contacts based on a complex mathematical algorithm that uses a code created by, and unique to, the phone’s user — and that Apple says it will not possess.

The result, the company is essentially saying, is that if Apple is sent a court order demanding that the contents of an iPhone 6 be provided to intelligence agencies or law enforcement, it will turn over gibberish, along with a note saying that to decode the phone’s emails, contacts and photos, investigators will have to break the code or get the code from the phone’s owner.

Breaking the code, according to an Apple technical guide, could take “more than 5 1/2 years to try all combinations of a six-character alphanumeric passcode with lowercase letters and numbers.” (Computer security experts question that figure, because Apple does not fully realize how quickly the N.S.A. supercomputers can crack codes.)