What are the best practices for data validation and sanitization to prevent security vulnerabilities?

When it comes to data validation and sanitization, there are several important best practices to follow:

• Input Validation: Validate all input data to ensure it meets the expected format and type.
• Parameterized Queries: Use parameterized queries to prevent SQL injection attacks.
• Encoding Output: Encode output data to prevent cross-site scripting attacks.
• Prepared Statements: Use prepared statements in SQL queries to protect against SQL injection.

Additionally, consider implementing whitelisting to only allow specified characters and patterns in input, as well as blacklisting to block known malicious inputs. Regularly sanitize and validate data to ensure ongoing security.