What is a key principle of secure coding?

Validating all user input is a fundamental principle of secure coding because it helps ensure that an application can only process the types of data that it is designed to accept. This practice is crucial for preventing various types of attacks, such as injection attacks, where an attacker tries to manipulate the application by inputting malicious data. By thoroughly checking and validating user inputs, developers can mitigate risks associated with unexpected or harmful data, thereby enhancing the security of the application.

While minimizing user input might seem beneficial, completely restricting input can hinder user experience and functionality. Displaying all error messages to users can inadvertently reveal sensitive information about the internal workings of the application, making it easier for attackers to exploit vulnerabilities. Additionally, maximizing access permissions contradicts the principle of least privilege, which advocates granting users only the permissions necessary to perform their tasks, thus reducing potential attack surfaces. Validating user input strikes a balance between functionality and security, making it a vital practice in secure coding.