Construction and Traversal of Hash Chain with Public Links.

Current hash chain traversal techniques require that the intermediate links of the hash chain be stored secretly on a trusted storage. This requirement is undesirable in several applications. We propose a new construction of hash chains based on inserting a ‘breakpoint ’ after fixed number of links in the chain. We also propose a method with which the current hash chain traversal techniques can be applied to our construction without any significant changes in the storage and computation requirements and with the added advantage that the intermediate links may be stored on a public and non-trusted storage. We are also able to prove the security of our construction by replacing the hash function with a MAC function. 1