Input Validation Sanitization

Input validation and sanitization is the practice of checking all data entering a function to ensure it meets expected criteria before processing. In smart contracts, failing to validate inputs can lead to various exploits, including invalid state changes or arbitrary code execution.

For instance, if a function accepts a contract address as an argument, it must verify that the address is trusted. Without this, an attacker could provide a malicious contract to trigger a harmful delegatecall.

Sanitization involves checking for correct data types, ranges, and authorized states. This is a basic but essential defense layer in all secure programming.

It is the first line of defense against many common smart contract vulnerabilities.