International Association
for Cryptologic Research

The recent advent of cloud computing and IoT has made it imperative to store huge amount of data in the cloud servers. Enormous amount of data is also stored in the servers of big organizations. In organizations, it is not desirable for every member to have equal privileges to access the stored data. Threshold secret sharing schemes are widely used for implementing such access control mechanisms. The access privileges of the members also vary from one data packet to another. While implementing such dynamic access structures using threshold secret sharing schemes, the key management becomes too complex to be implemented in real time. Furthermore, the storage of the users’ access privileges requires exponential space (O($2^n$)) and its implementation requires exponential time. In this paper, the algorithms proposed to tackle the problems of priority based access control and authentication require a space complexity of O($n^2$) and a time complexity of O($n$), where n is the number of users. In the practical scenario, such space can easily be provided on the servers and the algorithms can run smoothly in real time.