Blockchain has been growing rapidly in the cryptocurrency age and is one of the best information technologies that provide security and privacy to the data of people in crypto economy. In most cases, tampering with data and problems regarding data authentication tend to occur when data is shared and stored on centralized servers. With the assistance of blockchain technology, big data can be managed and saved in the cloud, and the technologies that enhance security by keeping out pernicious users could be used. Therefore, this paper has two aims: to discover the advantages and disadvantages of existing security big data models and to develop a conceptual secure big data model based on blockchain technology. The design science method is used for the purposes of this study. The developed conceptual secure big data model consists of three main processes: dataset storage and encryption, verification and consensus, and access control mechanism. The finding of this study discovered that the developed conceptual secure big data model offers a mix of both traditional and modern security measures which helps domain practitioners understand the security concepts of the blockchain along with big data as well.