Google’s Android, the most widely used smartphone operating system, seemed to have received even more attention. By 2016, the C.I.A. had 24 weaponized Android “zero day” software programs.

Did the C.I.A. directly target encryption software?

The C.I.A. focused on smartphone operating systems in large part to intercept messages before they could be encrypted, according to the WikiLeaks documents. So by targeting the phone’s underlying software, the C.I.A. was looking to bypass the encryption of WhatsApp, Signal, Telegram, Weibo and other smartphone communications applications.

They did not appear to find a way into the apps themselves.

Were other kinds of devices targeted?

The C.I.A. also targeted Microsoft’s Windows personal computer software, other internet-connected computers, and home and industrial devices running the Linux operating system, according to the documents.

There was a specific program to penetrate and take control of Samsung smart TVs. The program, code-named Weeping Angel, was intended to convert new digital televisions into “covert microphones.” The malware was developed in cooperation with the British spy agency MI5, according to the documents.

The Weeping Angel program puts the target TV in a “fake off” mode, according to the WikiLeaks documents. Then, with the owner believing the TV is turned off, the set works as a clandestine recording device, picking up conversations in the room and sending them over the internet to a C.I.A. server computer.

And in October 2014, according to the documents, the C.I.A. was exploring technology to penetrate the vehicle control systems of cars. The documents do not detail the goal of the vehicle hacking program, but WikiLeaks speculated that it would “permit the C.I.A. to engage in nearly undetectable assassinations.”

Has encryption software changed how the C.I.A. behaves?

The leaked documents indicate that the broad use of encryption has pushed the C.I.A. to become one of the world’s foremost creators — and buyers — of malware. Much of the cache released by WikiLeaks appears to show how the agency has created or acquired a variety of tools to thwart tough encryption or intercept messages before encryption tools make them useless to the intelligence agency.