Information Security Management System ISO 27001 and Information Technology Service Management System ISO 20000 are two different international standards, each with different concerns and applications.
ISO27001 is a standard for information security management systems that focuses on how to protect an organization's information assets and ensure that information security is adequately protected. This standard provides a framework and requirements to help organizations establish, implement, maintain, and continuously improve their information security management systems. At its core, ISO 27001 is risk management, which requires organizations to identify and assess information security risks based on their business needs and risk tolerance, and to put in place appropriate controls to mitigate them. In addition, the standard also requires organizations to establish information security policies, clarify information security objectives and responsibilities, conduct risk assessment and risk management, develop information security control measures, and monitor and review information security performance.
In contrast, ISO20000 is an information technology service management system standard that focuses on how to provide high-quality IT services to meet business needs. This standard provides a model to help organizations establish, implement, operate, monitor, review, and improve their IT service management systems. ISO20000 emphasizes the management of IT issues through "IT service standardization", that is, the classification of IT issues, the identification of internal relationships of problems, and then planning, implementation and monitoring according to service level agreements, and the emphasis on communication with customers. The standard also focuses on establishing standardized service processes and improving the efficiency of information technology services and operations.
Overall, ISO27001 and ISO20000 are both very important international standards, each of which provides organizations with different management frameworks and requirements to help them achieve better performance in information security and IT service management. While the two standards have different concerns and areas of application, they can also complement each other and work together to improve an organization's information security and IT service levels.