Addressing the Shortcomings of One-Way Chains

One-way hash chains have been the preferred choice, over the symmetric and asymmetric key cryptography, in security setups where efficiency mattered; despite the ephemeral confidentiality and authentication they assure. Known constructions of one-way chains (for example, SHA-1 based), only ensure the forward secrecy and have limitations over their length i.e., a priori knowledge of chain’s length is necessary before constructing it. In this paper, we will see how our approach, based on chameleon functions, leads to the generation of practically unbounded one-way chains with constant storage and computational requirements. We provide the construction and advantages of our proposal with the help of a secure group communication setup. We also provide the implementation details of our construction and argue its suitability for security setups, where one cannot a priori determine the longevity of the setup.