PORTLAND, Maine — One of the Navy's top cybersecurity officials says there's no evidence that a Navy warship has ever been hacked. And he wants to keep it that way with the Navy's most advanced destroyer.

Rear Adm. William Leigher said the stealthy Zumwalt that's under construction at Maine's Bath Iron Works represents the highest level of automation and integration to date on a destroyer.

Leigher says there will be exhaustive tests on the ship before it heads to sea.

Leigher, a Maine native, is in his home state to deliver a keynote address Friday at a University of Southern Maine conference bringing together public and private sector information technology officers.