Robert Morris, a cryptographer who helped develop the Unix computer operating system, which controls an increasing number of the world’s computers and touches almost every aspect of modern life, died on Sunday in Lebanon, N.H. He was 78.

The cause was complications of dementia, his wife, Anne Farlow Morris, said.

Known as an original thinker in the computer science world, Mr. Morris also played an important clandestine role in planning what was probably the nation’s first cyberwar: the electronic attacks on Saddam Hussein’s government in the months leading up to the Persian Gulf war of 1991.

Although details are still classified, the attacks, along with laser-guided bombs, are believed to have largely destroyed Iraq’s military command and control capability before the war began.

Begun as a research effort at AT&T’s Bell Laboratories in the 1960s, Unix became one of the world’s leading operating systems, along with Microsoft’s Windows. Variations of the original Unix software, for example, now provide the foundation for Apple’s iPhone iOS and Macintosh OSX as well as Google’s Android operating systems.