A botnet primarily utilizes compromised computers to perform coordinated attacks because it is a network of infected devices, often referred to as "bots" or "zombies." These devices are typically part of a larger scheme orchestrated by a cybercriminal, allowing them to control a vast number of machines simultaneously to execute various malicious activities.
The coordination among these compromised systems enables the botnet to execute large-scale attacks, such as Distributed Denial of Service (DDoS) attacks, where numerous bots flood a target with traffic to overwhelm it. This method proves highly effective for attackers, as they can leverage the combined resources of multiple machines to achieve their objectives, whether that's stealing data, distributing spam, or spreading malware.
In contrast, the other options do not accurately represent the primary function of a botnet. High bandwidth servers for data storage are typically more associated with cloud services and data management rather than the operations of a botnet. Encryption algorithms, while crucial for securing communications and protecting data, do not relate to the operational goals of a botnet itself. Finally, firewalls protect networks from unauthorized access, but they do not represent the mechanism through which a botnet operates; rather, they can be strategies for defending against such attacks.