Application whitelisting is a proactive cybersecurity approach that allows only known safe applications to execute, reducing the risk of malware and viruses. Unlike blacklisting, which reacts to newly identified threats, whitelisting helps prevent breaches by restricting unauthorized applications, addressing unique challenges in industrial control systems where safety and environmental risks are significant. The author, Rick Kaun, highlights the importance of thorough testing and scrutiny for whitelisting solutions within the industrial sector.