Why is input validation essential for security?

Input validation is essential for security primarily because it helps to ensure that only properly formatted and expected data is processed by an application. This process is crucial in preventing vulnerabilities that can be exploited by attackers. For instance, if an application does not properly validate input, an attacker might input harmful data, such as SQL injection scripts, which can lead to unauthorized access or manipulation of the database.

By implementing robust input validation, developers can prevent the processing of unexpected or harmful data types, thereby reducing the risk of security breaches. This minimizes the chances of incorrect data leading to vulnerabilities that could be exploited, ensuring that the application functions as intended and remains secure.

The other options, while they may pertain to aspects of software design or functionality, do not directly relate to the core purpose of input validation in the context of security.