Explanation
Availability means that service should be accessible at the required time and usable only by the authorized entity. Availability is one of the three main objectives of information security, along with confidentiality and integrity. Availability ensures that information and systems are not disrupted or denied by unauthorized actions or events. References: : CQI & IRCA ISO 27001:2022 Lead Auditor Course Handbook, page 24.
ISO/IEC 27001 Brochures | PECB, page 4.

The difference between a restricted and confidential document is that a restricted document is to be shared among named individuals, while a confidential document is to be shared among an authorized group.
Restricted and confidential are examples of information classification levels that indicate the sensitivity and value of information and the degree of protection required for it. Restricted documents contain information that could cause serious damage or harm to the organization or its stakeholders if disclosed to unauthorized persons. Therefore, they should only be accessed by specific individuals who have a legitimate need to know and are authorized by the information owner. Confidential documents contain information that could cause damage or harm to the organization or its stakeholders if disclosed to unauthorized persons. Therefore, they should only be accessed by a defined group of people who have a legitimate need to know and are authorized by the information owner. ISO/IEC 27001:2022 requires the organization to classify information in terms of legal requirements, value, criticality and sensitivity to unauthorized disclosure or modification (see clause
A.8.2.1). References: CQI & IRCA Certified ISO/IEC 27001:2022 Lead Auditor Training Course, ISO/IEC
27001:2022 Information technology - Security techniques - Information security management systems - Requirements, What is Information Classification?

Explanation
Information or data that are classified as public do not require labeling. Public information or data are those that are intended for general disclosure and have no impact on the organization's operations or reputation if disclosed. Labeling is a method of implementing classification, which is a process of structuring information according to its sensitivity and value for the organization. Labeling helps to identify the level of protection and handling required for each type of information. Information or data that are classified as internal, confidential, or highly confidential require labeling, as they contain information that is not suitable for public disclosure and may cause harm or loss to the organization if disclosed. References: : CQI & IRCA ISO 27001:2022 Lead Auditor Course Handbook, page 34. : CQI & IRCA ISO 27001:2022 Lead Auditor Course Handbook, page
37. : [ISO/IEC 27001 LEAD AUDITOR - PECB], page 14.

Explanation:

* The auditee is the organization or part of it that is subject to the audit. The auditee could be internal or external to the audit client . The auditee should cooperate with the audit team and provide them with access to relevant information, documents, records, personnel, and facilities .
* The audit client is the organization or person that requests an audit. The audit client could be internal or external to the auditee . The audit client should define the audit objectives, scope, criteria, and programme, and appoint the audit team leader .
* The technical expert is a person who provides specific knowledge or expertise relating to the organization, activity, process, product, service, or discipline to be audited. The technical expert could be internal or external to the audit team . The technical expert should support the audit team in collecting and evaluating audit evidence, but should not act as an auditor .
* The observer is a person who accompanies the audit team but does not act as an auditor. The observer could be internal or external to the audit team . The observer should observe the audit activities without interfering or influencing them, unless agreed otherwise by the audit team leader and the auditee .
References :=
* [ISO 19011:2022 Guidelines for auditing management systems]
* [ISO/IEC 17021-1:2022 Conformity assessment - Requirements for bodies providing audit and certification of management systems - Part 1: Requirements]