Table 3: Accountability requirements.

Interaction scenarioAccountability requirement

Customer travel agent(i) Mutual authentication between customer and travel agent.
(ii) Disclose traceability in service composition and the up-to-date booking status upon request.
(iii) Provide tamper proof evidences on booking transactions upon request.

Travel agent mapping service
Travel agent location provider
Travel agent fight provider
Travel agent hotel
Travel agent eCommerce
(i) Mutual authentication between travel agent and the external service sources.
(ii) Ensure integrity of the service source. This implies fulfillment of the requirements in the terms and conditions of the service source, ensuring the service providers’ copyright and trademarks are not breached.
(iii) Service source’s reputation is tracked and measured against the agreed quality of the services.
(iv) Provide tamper proof evidences on service transactions upon request.