Hash-Based Signatures for Bitcoin's Post-Quantum Future

The discussion on the trade-offs of Post-Quantum (PQ) signature sizes and their impact on performance, especially on low-power devices, gains practical insights from the Cellframe project. This project, which has been operational for several years, utilizes a C-based blockchain implementation that supports multiple NIST-candidate post-quantum algorithms, including Crystal-Dilithium/ML-DSA, among others. The focus of Cellframe is on hardware optimization, targeting not only high-performance nodes but also low-end embedded devices. This approach has enabled the collection of significant real-world data that could be beneficial to the ongoing discussions about PQ transitions in various technologies like Bitcoin.

The project's findings highlight two main areas: the memory footprint and verification times of different signature algorithms on constrained hardware. Specifically, it provides concrete data on the dynamic RAM usage differences between Lattice-based and Hash-based signatures and offers insights into signing and verification times on low-power ARM architectures when the code is highly optimized in C. These findings are particularly relevant for understanding the practical implications of implementing PQ cryptography in environments where resources are limited.

The willingness of the Cellframe project to share benchmarks and optimization techniques presents an opportunity for the working group to validate theoretical constraints with empirical data. This collaboration could significantly enhance the understanding of signature size overheads and performance impacts in live production environments, thereby informing more effective strategies for Bitcoin's transition to Post-Quantum cryptography.