A mixed adversary is one who can disrupt the network in a variety of ways. He may corrupt certain nodes in Byzantine fashion, certain nodes in a fail stop fashion and some nodes in a passive way. We see that it is a non-trivial task to extend the protocols that tolerate a Byzantine adversary to a mixed adversary and we introduce new techniques to design protocols tolerating mixed adversary. A mobile adversary is capable of changing the set of nodes under its influence in every round of the execution of the protocol. Designing protocols tolerating such an adversary calls for a fresh look at the problem and we give optimal protocols running in constant rounds for this issue.
Professor Pandu Rangan obtained his PhD from the Indian Institute of Science (Bangalore, India). Since 1982, he serves as a faculty member in the department of Computer Science and Engineering of the Indian Institute of Technology (Madras). He joined the rank of professors in 1995 and served as Head of Department from 1998 to 2001. He was recently honored as Fellow of the Indian National Academy of Engineering (INAE). He served as a member of the board of Directors of the International Association for Cryptologic Research (IACR) from 2002 to 2005. He is currently in the editorial board of LNCS published by Springer-Verlag and in the editorial board of the Journal of Parallel and Distributed Computing. He served as PC chair/General chair for a number of leading conferences such as ASIACRYPT and INDOCRYPT. He has published extensively in various reputed international journals and conferences covering a vast range of topics in algorithms and cryptology. In algorithms, his research focus is in graph algorithms, randomized algorithms and parallel algorithms. In cryptology, he is focusing in secure/reliable message transmission which is a key problem to solve multiparty computations.