Cloud computing is designed to provide services to the end users and to the owners of organizations over internet with little cost and with little configuration effort. There are many concerns about cloud computing especially in terms of security, privacy, and trust. These main issues have prevented business from fully accepting cloud platforms. Some of the confidential Business-to-Bussiness (B2B) collaborations require secure tunnels to secure the messaging between the services that are deployed within the same cloud. As organizations participating in B2B collaborations deploy their services in single or multiple clouds, businesses face security threat to their sensitive data both from outside and inside the cloud. This work is proposed to contribute in solving such problems. This paper presents an electronic contract (econtract) based solution that provides a secure Connectivity as a Service (CaaS) for intra-cloud communications. Our proposed model interestingly handles secure messaging for the services deployed within the same cloud. The basicinterction model has further been enhanced by adding a new service layer (Authentication Service) which is responsible for offering a high level of trust between collaborating parties by preventing any unauthorized party from joining the connectivity service. Indeed, our proposed system can prevent any involved organization from launching masquerade attacks. The added layer basically facilitates the integration of the basic model with the Public-Key Infrastructure (PKI). The proposed system can also be helpful in solving other attacks such as man-in-the-middle attack and modification of the messages attack.