The Smart Grid has emerged to address the shortcomings of one-way existing grid systems, and is the next generation power grid infrastructure that applies smart ICT (Information Communication Technology) to existing grid. The Smart Grid is expected to greatly improve the efficiency and reliability of future power systems with the demand for renewable energy resources. However, because major power facilities are interconnected through communication networks, Smart Grid’s cyber security is becoming an important issue. Cyber-attacks by malicious intruders can lead to serious incidents such as massive outages and the destruction of power network infrastructure, since the cyber-attacks can damage energy data, starting with personal information leakage from grid members. Therefore, as a solution to this issue we will suggest a secure smart energy management system based on the blockchain. The blockchain is a distributed data processing technology in which all users participating in the network distribute and store data. Applying blockchain technology to the Smart Grid will enable more secure management of energy data, and furthermore, it will contribute to the development of the future smart energy industry in the future.