Distributing the Key Distribution Centre in Sakai–Kasahara Based Systems

One major drawback with using Sakai–Kasahara based identity-based secret keys is that it appears hard to distribute the trust of the key generation centre. For other types of identity based key this distribution can be done using non-interactive and simple techniques. In this short note we explain how this can be done for Sakai–Kasahara style keys using a simple application of a general technique from multi-party computation. The self-checking property of the resulting private key we show can be used to insulate the protocol from malicious adversaries for many practical parameter sizes.