In order to solve the confidentiality problem in blockchain application, we proposed a novel secure computation framework based on smart contract and hardware security module. It allows user to send a request to certified secure-computing-module (SCM) to compute the program sent from user and it can be proved whether the computing request is executed correctly through the blockchain mechanism. In addition, it should be verified that the unauthorized user would not be able to access the content of computing request. The main function of a SCM is to accept the computing request. SCM is designed for receiving requests from users and it would execute the requests under the initial requirement set by users. Moreover, only the authorized party could access the data in stored in smart contract which is encrypted by users through the access control mechanism and encryption key sharing algorithm.

The proposed framework provides a general purposed solution of confidentiality and privacy which are problems to be solved in original blockchain technology. Users can deploy their programs to SCMs, and it is ensured that the program would be executed correctly by SCM. Moreover, cryptographic algorithm guarantees that there is no information leak in the process.

The framework is suitable for the following applications:
• A process involves several different parties with conflicted interests
• The parties need a mechanism to improve trustworthy among the parties
• The process should consider confidentiality
• The process should be executed with trusted logs.