Encryption is the process of encoding data in a way that prevents unauthorized access. Encryption is commonly applied in two ways. One is to encrypt the entire disk storage. This type of encryption can only be effective when the system is stopped, or the drive ejected. Another one is called granular encryption, which encrypts specific data at different granularity levels while the application is running. Although many granular encryption methods have been proposed, data security has not been fully achieved. In this paper, we propose a novel pixel-based granular encryption method to better protect sensitive user data in database systems. Our experimental results show that the proposed encryption method is not only more secure, but also generally faster than other existing text-based encryption methods, and it takes less time to encrypt long digits of data.