Abstract: In recent years,the development of big data for public security is accelerating.The unified construction of public security data centers around the country has brought about high centralization of sensitive data,thus the risk of leakage of information regarding national security and illegal use of personal information is sharply increasing.On the basis of traditional data security protection methods such as data encryption and role-based access control,this paper presents a new access control model based on data grade and classification.Based on the grading and classification of data sensitivity,personnel and data,this model can achieve hierarchical control based on the level of data table,data field and data record,which is helpful to achieve precise access authorization control of grading and classification for sensitive public security data with higher flexibility and finer granularity,and can be effectively applied to the construction of data access security control system of modern big data cloud platform for smart public security.This model has been applied to the construction of smart public security in some areas and has achieved satisfied results.

Key words: Authorized access, Big data, Graded and classified access control, Public security cloud, Sensitive data