AMSA: Adaptive Merkle Signature Architecture
Emanuel Regnatha and Sebastian Steinhorstb
Technical University of Munich, Germany
aemanuel.regnath@tum.de
bsebastian.steinhorst@tum.de
ABSTRACT
Hash-based signatures (HBS) are promising candidates for quantum-secure signatures on embedded IoT devices because they only use fast integer math, are well understood, produce small public keys, and offer many design parameters. However, HBS can only sign a limited amount of messages and produce – similar to most post-quantum schemes – large signatures of several kilo bytes.
In this paper, we explore possibilities to reduce the size of the signatures by 1. improving the Winternitz One-Time Signature with a more efficient encoding and 2. offloading auxiliary data to a gateway.
We show that for similar security and performance, our approach produces 2.6 % smaller signatures in general and up to 17.3 % smaller signatures for the sender compared to the related approaches LMS and XMSS. Furthermore, our open-source implementation allows a wider set of parameters that allows to tailor the scheme to the available resources of an embedded device, which is an important factor to overcome the security challenges in IoT.
Keywords: Hash, Signature,WOTS, IoT.
