What does "input validation" ensure?

Input validation is a crucial security measure that ensures the data provided to a software application is checked for correctness and security before it is processed. This process validates the data against predefined criteria, such as data type, format, length, and allowable values. By implementing input validation, software applications significantly reduce the risk of vulnerabilities, such as injection attacks, buffer overflows, and other forms of malicious data manipulation.

This practice helps to ensure that only well-formed, expected data is accepted by the application, which in turn helps to maintain the integrity and security of the software. When improper or malicious input is filtered out before reaching the application logic, it protects both the application and the larger system from potential harm. Thus, input validation serves as a foundational element in creating secure software designs.