Distributed Public Key Cryptosystems

ABSTRACT
Distribution of a cryptographic function among a set of servers is a crucial enhancement to basic cryptographic primitives. It enables increased security due to the diffusion of secure memories and increased availability due to redundancy; this increases the trust in the overall system. Distribution also enables flexible management of cryptographic primitives (signature or decryption service), since it makes it possible for a complex organization to control and organize sensitive functions while the organization changes. Much activity has been taken place in the last few years concentrating on designing efficient, flexible and secure ``distributed public key cryptosystems''. Furthermore, such systems have even become a reality (due to actual user needs). We will review the basic security notions, design issues, building blocks and algorithms, as well as proof techniques that we have developed recently in this area.