ISO/IEC 27701, adopted in 2019, added additional ISO/IEC 27002 guidance for PII controllers.

Here is the relevant paragraph to articles 26(1), 26(2), and 26(3) GDPR:

7.2.7 Joint PII controller

Control

The organization should determine respective roles and responsibilities for the processing of PII (including PII protection and security requirements) with any joint PII controller.

Implementation guidance

Roles and responsibilities for the processing of PII should be determined in a transparent manner.

These roles and responsibilities should be documented in a contract or any similar binding document that contains the terms and conditions for the joint processing of PII. In some jurisdictions, such an agreement is called a data sharing agreement.

A joint PII controller agreement can include (this list is neither definitive nor exhaustive):

— purpose of PII sharing / joint PII controller relationship;

— identity of the organizations (PII controllers) that are part of the joint PII controller relationship;

— categories of PII to be shared and/or transferred and processed under the agreement;

— overview of the processing operations (e.g. transfer, use);

— description of the respective roles and responsibilities;

— responsibility for implementing technical and organizational security measures for PII protection;

— definition of responsibility in case of a PII breach (e.g. who will notify, when, mutual information);

— terms of retention and/or disposal of PII;

— liabilities for failure to comply with the agreement;

— how obligations to PII principals are met;

— how to provide PII principals with information covering the essence of the arrangement between the joint PII controllers;

— how PII principals can obtain other information they are entitled to receive; and

— a contact point for PII principals.