What is the primary purpose of compressing and encrypting a payload?

The primary purpose of compressing and encrypting a payload is to change its signature and evade detection by security software. When data is compressed, it may appear differently in terms of its structure and size, which can help it bypass certain security measures that analyze data patterns for potential threats. Encryption adds an additional layer of obfuscation, making the content unreadable without the appropriate decryption key. This combination not only helps in disguising the true nature of the data but also makes it more challenging for security tools to perform signature-based detection, crucial for attackers looking to avoid detection when transmitting malicious payloads.

The other options, while they may have their own merits in different contexts, do not encapsulate the primary intent behind compressing and encrypting a payload in a security context. For example, improving transmission speed or reducing storage size is not the main objective when security is the focus, and simplification for user understanding diverges entirely from the need for security and evasion tactics.