Binary Pebbling Algorithms for In-Place Reversal of One-Way Hash Chains

The resourcefulness of people working in the area of cryptology is striking. A wonderfully diverse set of professionals capable of generating an almost endless stream of new, intriguing research problems and, fortunately—driven by the ever faster changing playing field of our information society and infrastructure under attack—capable of finding many ingenious and compelling solutions as well. Unsurprisingly, mathematics plays a central role in cryptology along with computer science. The algorithmic problem chosen as the topic of this paper has a unique motivation in cryptography. At the core of its solution lies an intricate fractal structure which turns out to have a very nice and simple characterization.