This paper deals with largely two security problems between the cloud computing service and trusted platform module (TPM) chip as a mobile convergent technology. At first, we solve the social issues from inside attackers, which is caused by that we regard server managers as trustworthy. In order to solve this problem, we propose encrypted DB retrieval system whose server manager cannot access on real data (plaintexts) in mobile office environments of the cloud datacenter. The other problem is that cloud computing has limitless computing resources; however, it faces with the vulnerability of security. On the other hand, the TPM technology has been known as a symbol of physical security; however, it has the severe limitation of use such as hardware constraints or limited amount of non-volatile memory. To overcome the weakness and produce synergic effects between the two technologies, we combine two applications (cloud datacenter service, TPM chip) as a mobile convergent technology. The main methods are TPM-security-client and masked keys. With these methods, the real keys are stored in TPM and the faked keys (masked keys) are implemented for computations instead of real keys. Thus, the result of the faked keys is the same as the real keys. Consequently, this system is secure against both of the insiders and outsiders, the cloud computing service can improve security weaknesses.