What is the primary purpose of ransomware?

Ransomware primarily functions by encrypting files on a victim's device or network, rendering them inaccessible to the user. The attackers then demand a ransom payment, typically in cryptocurrency, in exchange for the decryption key required to restore access to the files. This method strikes at the heart of users' critical data, causing significant disruption and prompting victims to consider paying the ransom in a desperate attempt to regain control of their information.

The other options represent different types of malware or malicious activity. For instance, stealing data silently refers to spyware or certain types of data breaches, while displaying unwanted ads pertains to adware, which generates income for its developers through advertising. Replication and spread are characteristic of viruses and worms that aim to propagate themselves across systems, which is unrelated to the core function of ransomware that focuses solely on infiltration, encryption, and ransom demands.