Abstract
At ACSAC 2019, we introduced a new cryptographic primitive called proof of aliveness (PoA), allowing us to remotely and automatically track the running status (aliveness) of devices in the fields in cyber-physical systems. We proposed to use a one-way function (OWF) chain structure to build an efficient proof of aliveness, such that the prover sends every node on the OWF chain in a reverse order periodically. However, the finite nodes in OWF chains limited its practicality. We enhance our first PoA construction by linking multiple OWF chains together using a pseudo-random generator chain in our second PoA scheme. This enhancement allows us to integrate one-time signature (OTS) schemes into the structure of the second construction to realize the auto-replenishment of the aliveness proofs for continuous use without interruption for reinitialization. In this work, our primary motivation is to further improve our secondary PoA and auto-replenishment schemes. Instead of storing the tail nodes of multiple OWF chains on the verifier side, we use a Bloom Filter to compress them, reducing the storage cost by <inline-formula><tex-math notation="LaTeX"> 4.7</tex-math> <mml:math><mml:mrow><mml:mn>4</mml:mn><mml:mo>.</mml:mo><mml:mn>7</mml:mn></mml:mrow></mml:math><inline-graphic xlink:href="yang-ieq1-3335188.gif"/> </inline-formula> times. Moreover, the OTS-based auto-replenishment solution cannot be applied to our first scheme, and it is not so efficient despite its standard model security. To overcome these limitations, we design a new auto-replenishment scheme from a hash-based commitment under the random oracle model in this work, which is much faster and can be used by both PoA schemes. Considering the implementation on a storage/memory-constrained device, we particularly study the strategies for efficiently generating proofs.