Technical Report TR-98-6ID, LCIS, Tamkang University, Taiwan, R.O.C., May 1998.

Abstract. This paper considers the problem of how to generate and recover a sequence of independent keys with the special property that allowing the key owner to release part of the keys to others when required. A novel usage of cryptographic hash chains will be used to solve the above problem. Applications of the proposed key generation scheme will also be considered.