Which of the following is a popular Python library used in cybersecurity?

Scapy is a powerful and versatile Python library specifically designed for network interaction, making it hugely popular in the field of cybersecurity. Its capabilities include packet manipulation, crafting custom packets, and performing network scanning and analysis, which are essential skills in cybersecurity practices. Scapy allows security professionals to easily perform tasks such as sniffing network traffic, forging packets, or building complex protocols, which is critical for penetration testing and security assessments.

In contrast, while Numpy, Pandas, and Flask serve important functions within the broader Python ecosystem, they are not focused on cybersecurity. Numpy is primarily used for numerical computations, Pandas for data manipulation and analysis, and Flask for web application development. Each of these libraries serves distinct purposes that do not directly contribute to cybersecurity tasks like those handled by Scapy. Thus, Scapy stands out as the relevant choice for professionals in cybersecurity.