Integrity is one of the three pillars of the CIA Triad (alongside Confidentiality and Availability) and ensures that data remains accurate, complete and trustworthy throughout its lifecycle — protected against unauthorised or accidental modification. It is maintained through access controls, change management, hashing and checksums, digital signatures, input validation and audit logging.
A loss of integrity — whether from a malicious tamper, a faulty process or human error — undermines the reliability of every decision made on that data. ISO 27001 addresses integrity through Annex A controls covering change management, cryptography, logging and monitoring, and secure development. Organisations verify integrity by detecting and correcting unauthorised changes and by keeping a tamper-evident record of what changed, when and by whom.