Information security is the practice of protecting data and information systems from unauthorised access, disclosure, alteration, or destruction. In Australia, information security is critical for organisations handling personal, financial, or classified information, particularly under the Privacy Act and sector-specific regulations. Information security encompasses confidentiality, integrity, and availability (the CIA triad), supported by technical controls such as encryption, access management, firewalls, and monitoring systems. It also includes governance measures such as policy frameworks, staff training, and incident response planning. Aligning information security programs with ISO 27001 and the ACSC Essential Eight enhances resilience against ransomware and data breaches. Strong information security practices protect intellectual property, customer trust, and regulatory standing in an increasingly digital economy.