الملخص

Multilevel Security (MLS) is one of the ways that protects the stored information in the computer and mobile devices. It classifies users and information into levels of security; thus, the user can access information within its level or less. A smartphone is used in managing some of businesses, controlling the home and car devices within the smart city environment by using a set of data stored in the database. The database is used by more than one authorized user some of this data is confidential and important that requires protection from un authorized users. In this research a proposed system to implement the MLS principle within three levels of security is presented. The first level gives the user its own security level. The second level transfers users through the system parts according to their security level (system administrator or regular user). The third level allows users to manipulate the stored encrypted data in SQLite database by using a simple and quick cryptographic algorithm. The proposed system is implemented in the smart mobile devices which are supported by the Android operating system. The experimental result showed that the proposed system has the ability to protect the data in the database and prevents users to view the data at upper levels. Also, the inability of users to change the security level of data that prevents the leak of data from the upper security levels to the lower level. Moreover, the proposed system works quickly and needs a little storage space.