ISO 27018 ISO 27018 vs GDPR

GDPR creates binding duties for controllers and processors. ISO 27018 does not replace those duties and does not decide whether you are legally a controller or processor. It gives a structured set of cloud privacy controls for providers acting as processors.

A strong program uses GDPR to define the legal outcome and ISO 27018 to define the operational mechanism and the evidence trail.

GDPR Article 28 requires the processor to act only on documented instructions from the controller. ISO 27018 reinforces this in cloud specific terms by saying that PII under contract should not be processed for any purpose independent of customer instructions.

This is the control area where teams usually discover hidden reuse of customer data for analytics, product features, or marketing.

GDPR Article 28 requires confidentiality commitments for persons authorized to process personal data, and Article 32 requires appropriate security of processing. ISO 27018 adds cloud specific implementation guidance around access administration, confidentiality obligations that survive termination, logging, cryptography disclosures, and user control boundaries.

The useful move is to treat confidentiality, access, logging, and cryptography as one evidence family rather than separate checklist items.

GDPR requires prior specific or general written authorization for subprocessors and requires the same data protection obligations to flow down. ISO 27018 makes this operational by requiring disclosure before use, timely notice of intended changes, names of relevant subprocessors, and the countries where they can process data.

That country level detail is where many processor programs are weak, especially when backup or support subprocessors are involved.

GDPR does not give you a full operating procedure for law enforcement or other third party disclosure requests. ISO 27018 does. It requires notification of legally binding requests unless prohibited, rejection of requests that are not legally binding, consultation where lawful, and recording of the disclosure and the authority behind it.

This is a major operational benefit of ISO 27018 because cloud providers receive these requests in many different forms and jurisdictions.

GDPR Article 33 places the main regulator notification duty on the controller, while processors must notify the controller without undue delay after becoming aware of a personal data breach. ISO 27018 fits this well by requiring prompt customer notice and detailed incident records, plus the contract definition of the maximum delay and required information fields.

The combination works well when the cloud provider maintains a breach record that already contains the information the customer needs for legal assessment.

GDPR Article 28 requires deletion or return of personal data at the end of the provision of services and requires the processor to make available information necessary to demonstrate compliance. ISO 27018 adds concrete cloud specific guidance for return, transfer, disposal, backup and business continuity erasure, and the use of independent assurance when direct customer audits are impractical.

That makes ISO 27018 especially useful for multi-tenant services where customer audits need a controlled alternative.

The most efficient approach is to build one processor evidence pack that satisfies customer legal review and customer security review at the same time. The pack should map contract clauses to control owners, procedures, and live records.

If you split GDPR evidence and ISO 27018 evidence into separate repositories, the story will drift and customer trust will drop.