It was a call to action. As Ms. Zezza searched for ways to protect sensitive data, she settled on WatchDox. The service gives file creators the ability to manage who can view, edit, share, scan and print a file, and for how long. If hackers steal the file off someone’s computer, all they will see is a bunch of encrypted characters.

Her biggest challenge, however, wasn’t hackers. It was co-workers. “Nobody wanted to use it,” Ms. Zezza said. “The first year was unbelievably painful. I was teased mercilessly.”

That was, of course, before the hacking at Sony. Now some Hollywood studios are removing their movie editing software from the Internet so hackers cannot get to it, said Ray Rothrock, the chief executive of RedSeal, a security start-up.

For years, oil companies have been doing something similar with their pipelines — a process known as “air-gapping”— so that if hackers breach their internal network, they can’t use that access to blow up a pipeline. Now, Mr. Rothrock said, Hollywood is doing the same to combat theft.

At WatchDox, demand from Hollywood studios has surged over the last three months, said Adi Ruppin, the chief technology officer. The company, which is based in Palo Alto, Calif., has for some time been working with people like Oren Peli, the producer and screenwriter behind the “Paranormal Activity” film franchise.

“Beyond a certain level, nothing is 100 percent foolproof, but now we know there are measures that make it 99 percent,” Mr. Peli said. “I’m a little paranoid, but it’s justified.”

In 2009, a 43-page outline of Mr. Peli’s coming film, “Area 51,” leaked online. Mr. Peli had relied on traditional techniques, like watermarking, or would even change words or names of minor characters in each version of a script to thwart leakers.