Electronic Signature System with Small Number of Private Keys

We propose a simple server-based electronic signature system in which a small number of common private keys are used. The motivation of such a system is to escape the scalability and complexity problems that arise if a large-scale Public Key Infrastructure (PKI) is used. We argue that the assumption of personal private keys is the main reason for those problems and high cost of electronic signature systems. We conclude that elimination of personal private keys is justified and further argue that this does not reduce the security.