Variable Member Group Authentication Protocol using Bivariate Polynomials
Suresh Grandhi1, P. S. Avadhani2

1Suresh Grandhi*, Research Scholar, Department of Computer Science and Systems Engineering (CSSE), A. U. College of Engineering, Andhra University, Vizag (Andhra Pradesh), India.
2Dr P S Avadhani, Professor, Department of Computer Science and Systems Engineering (CSSE), A. U. College of Engineering, Andhra University, Vizag (Andhra Pradesh), India.
Manuscript received on February 10, 2020. | Revised Manuscript received on February 26, 2020. | Manuscript published on March 10, 2020. | PP: 2269-2274 | Volume-9 Issue-5, March 2020. | Retrieval Number: B7101129219/2020©BEIESP | DOI: 10.35940/ijitee.B7101.039520
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Abstract: Group authentication is required for secure group communication, which ensures that users in the group are valid. When a group user count is not fixed, group authentication has to handle the entry of new users and exit of current users from the group, if necessary. The challenges to group communication are Security, Integrity and Confidentiality. Currently, available group authentication schemes are complex that require heavy computation and communication overheads. Whenever the group membership is changed, the rekeying of group key process is a challenging task. Thus, in this paper, we propose a variable number group authentication mechanism based on the Lagrange interpolation using bi-variate polynomials. Our proposed scheme handles the generation of the group key and validation effectively. The proposed model shares secret keys to the group user and authenticates all users participated in the group using a single computation and individual users when required. The proposed scheme has a group manager (GM) authenticating all group users and also generates a group key for validating member authenticity. GM is responsible for authenticating and validating each user in the group. GM takes care of members entry and exit from the group. During the changes to the group membership, rekeying is necessary. Our proposed scheme efficiently handles the rekeying process. The proposed scheme also handles backward and forward confidentiality during the group conversation. The security analysis of our scheme guarantees Forward Secrecy, Backward Secrecy, Integrity, Confidentiality and Availability. Our proposed method works effectively for dynamic group communications, where the group membership changes quite frequently. 
Keywords: Group Authentication, Variable Group Members, Lagrange Interpolation, Bi-variate Polynomials, Group communication.
Scope of the Article: Authentication, authorization, accounting