1. Center for Security, Theory and Algorithmic Research; International Institute of Information Technology; Hyderabad 500 032 India
2. Department of Mathematics; Chaudhary Charan Singh University; Meerut 250 005 Uttar Pradesh India
3. Department of Mathematics; Indian Institute of Technology; Kharagpur 721 302 India
4. Department of Computer Science and Engineering; Indian Institute of Information Technology; Chittoor Sri City 517 588 Andhra Pradesh India
5. Department of Computer Science and Engineering; Xiamen Institute of Technology; Xiamen 361 021 China
6. School of Computer Science and Engineering; Hunan University of Science and Technology; Xiangtan 411 201 China