Timothy D. Cook, Apple’s chief executive, last month telegraphed what his employees might do in an email to customers: “The same engineers who built strong encryption into the iPhone to protect our users would, ironically, be ordered to weaken those protections and make our users less safe,” Mr. Cook wrote.

Apple declined to comment.

The fear of losing a paycheck may not have much of an impact on security engineers whose skills are in high demand. Indeed, hiring them could be a badge of honor among other tech companies that share Apple’s skepticism of the government’s intentions.

“If someone attempts to force them to work on something that’s outside their personal values, they can expect to find a position that’s a better fit somewhere else,” said Window Snyder, the chief security officer at the start-up Fastly and a former senior product manager in Apple’s security and privacy division.

Apple said in court filings last month that it would take from six to 10 engineers up to a month to meet the government’s demands. However, because Apple is so compartmentalized, the challenge of building what the company described as “GovtOS” would be substantially complicated if key employees refused to do the work.

Inside Apple, there is little collaboration among teams — for example, hardware engineers usually work in different offices from software engineers.

But when the company comes closer to releasing a product, key members from different teams come together to apply finishing touches like bug fixes, security audits and polishing the way the software looks and behaves.

A similar process would have to be created to produce the iPhone software for the Federal Bureau of Investigation. A handful of software engineers with technical expertise in writing highly secure software — the same people who have designed Apple’s security system over the last decade — would need to be among the employees the company described in its filing.