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Authentication

11/09/2025

Author: Stuart Barker | ISO 27001 Expert and Thought Leader

Authentication Definition - ISO 27001 Glossary

Authentication is the process of verifying the identity of a user, person, or device. In the context of information security, it confirms that a user is who they claim to be before granting them access to a system, application, or network. It is a critical component of access control.

Common Methods & Examples

  • Something you know: Knowledge-based factors.
    • Example: A username and password, or a PIN.
  • Something you have: Possession-based factors.
    • Example: A keycard, a physical token, or a one-time code sent to your phone.
  • Something you are: Inherence-based factors.
    • Example: Biometrics, such as a fingerprint, facial scan, or voice recognition.

ISO 27001 Context

ISO 27001 requires robust authentication mechanisms to protect information assets (ISO 27001 Annex A 8.5 Secure Authentication). It includes a requirements on authentication information (ISO 27001 Annex A 5.17 Authentication Information).

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Stuart Barker, ISO 27001 expert

Stuart Barker
ISO 27001 Expert and Thought Leader

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Stuart Barker, ISO 27001 expert

About the author

Stuart Barker is an information security practitioner of over 30 years. He holds an MSc in Software and Systems Security and an undergraduate degree in Software Engineering. He is an ISO 27001 expert and thought leader holding both ISO 27001 Lead Implementer and ISO 27001 Lead Auditor qualifications. In 2010 he started his first cyber security consulting business that he sold in 2018. He worked for over a decade for GE, leading a data governance team across Europe and since then has gone on to deliver hundreds of client engagements and audits.

He regularly mentors and trains professionals on information security and runs a successful ISO 27001 YouTube channel where he shows people how they can implement ISO 27001 themselves. He is passionate that knowledge should not be hoarded and brought to market the first of its kind online ISO 27001 store for all the tools and templates people need when they want to do it themselves.

In his personal life he is an active and a hobbyist kickboxer.

His specialisms are ISO 27001 and SOC 2 and his niche is start up and early stage business.