Putting Wings on SPHINCS

SPHINCS is a recently proposed stateless hash-based signature scheme and promising candidate for a post-quantum secure digital signature scheme. In this work we provide a comparison of the performance when instantiating SPHINCS with different cryptographic hash functions on both recent Intel and AMD platforms found in personal computers and the ARMv8-A platform which is prevalent in mobile phones. In particular, we provide a broad comparison of the performance of cryptographic hash functions utilizing the cryptographic extensions and vector instruction set extensions available on modern microprocessors. This comes with several new implementations optimized towards the specific use case of hash-based signature schemes. Further, we instantiate SPHINCS with these primitives and provide benchmarks for the costs of generating keys, signing messages and verifying signatures with SPHINCS on Intel Haswell, Intel Skylake, AMD Ryzen, ARM Cortex A57 and Cortex A72.