How To Re-initialize a Hash Chain

Hash Chains are used extensively in various cryptographic systems such as onetime passwords, server supported signatures, secure address resolution, certificate revocation, micropayments etc. However, currently they suffer from the limitation that they have a finite number of links which when exhausted requires the system to be re-initialized. In this paper, we present a new kind of hash chain which we call a Re-initializable Hash Chain (RHC). A RHC has the property that if its links are exhausted, it can be securely re-initialized in a non-repudiable manner to result in another RHC. This process can be continued indefinitely to give rise to an infinite length hash chain, or more precisely, an infinite number of finite length hash chains tied together. Finally we illustrate how a conventional hash chain (CHC) may be profitable replaced with a RHC in cryptographic systems.