Efficient targeted key subset retrieval in fractal hash sequences

Abstract

This paper presents a new hash chain traversal strategy which improves performance of hash chain based one-time authentication schemes. This work is motivated by the need for efficient message authentication in low-latency multicast systems. Proposed solutions such as TV-OTS rely on hash chain generated values for keys, achieving reliable security by using only a small subset of generated values from each chain. However, protocols using hash chains are limited by the rate at which a hash chain traversal is able to supply keys. The new algorithm uses the same structure as Fractal Hash Traversal, but eliminates redundant operations incurred when used with applications such as TV-OTS. Performance is measured in terms of savings and is proportional to the chain-distance between consecutively retrieved values. For a distance of δ, we achieve Θ(δ log 2 (δ)) savings, which is shown analytically and supported by empirical tests.

Secure broadcast in distributed networks with strong adversaries

“…For example, under a brute‐force attack, the BC starts from initial keys and tries to find the leaked key by updating the sequence of keys one by one. Such a strategy can be optimized .…”