The lack of coordination in the integration of information systems between government agencies that issue identity numbers causes replication and redundancy of population information data. Another problem is the emergence of citizens' concerns over data integrity and security due to national identification records is also used by the private sector. In this paper, one of the solutions offered to overcome the above problem is to build an integrated national identification database system between government agencies by applying the concept of Single Identity Number (SIN) using blockchain technology. Blockchain is a secure and robust system for keeping a record of the identities of all citizens and also able to facilitate data integration between institutions. This paper uses the strengths of blockchain to possess characteristics of immutability that it is possible to store national identification records.