The CA:Sec (Canadian Network Security) Implementation Guidance specifies the foundational elements needed to securely execute transactions between two systems.
CA:Sec is based on the ATNA profile and aims to bring improvements via loose coupling, and high cohesion, with focus on secure communication.
For more details see IHE ATNA profile, RESTful ATNA Supplement and ATNA ITI-19 transaction documentation.
Note: In addition to secure communication that is covered in CA:Sec, there are other critical aspects that need to be implemented to achieve a high degree of cybersecurity, see Security Considerations.