In the weeks after Donald J. Trump won the election, a schism threatened to break my group of friends in two. Not a political argument brought about by the president-elect, or a philosophical fight over the future of the country, but a question of which app we should be using to chat: GroupMe or Signal?

On the one hand, GroupMe, a popular group-messaging app, had cartoons we could add to our conversations, and we’d been using it for years. On the other, Signal offered secure, encrypted communication, and we were facing the first term of a president who has said Edward J. Snowden should be executed, demanded a boycott of Apple when the company refused to crack the iPhone of the San Bernardino, Calif., gunman for the F.B.I., and openly admired the “power” of the hackers who leaked emails from the Democratic National Committee. Sure, we were mostly plotting bars to meet at, not targets for terrorist attacks. But given the incoming administration’s professed attitude, a little extra security couldn’t hurt. Then again: GroupMe’s cartoons were really fun.

We weren’t the only people asking ourselves this kind of question. In the months since the hacking of the Democrats and Mr. Trump’s election, information security has become a concern to a much larger group of people than the professionals, activists, journalists and paranoiacs you’d expect. (Even stalwart Trump supporters on Reddit and in the comments on Breitbart are expressing apprehension about a congressional vote on Tuesday that rolled back Obama-era privacy regulations governing the collection of user data by internet service providers.) Nowhere is this more clear than in consumer apps and services for secure communications.

Though it’s still not challenging Facebook Messenger atop the most-downloaded rankings, Signal, an open-source secure-messaging service produced by Open Whisper Systems, had a 400 percent increase in downloads in the days after the election, an incredible spike for an app developed by a small team funded by grants and donations. “Millions of people used Signal before the election,” Moxie Marlinspike, the founder of Open Whisper, told me recently, “but there has never before been a single event that resulted in such a dramatic and sustained day-over-day increase in new Signal users.”