Bitcoin Rails
Bitcoin's Leading Post-Quantum Signature Proposal | CONDUITION
- Conduition co-authored a full specification for SHRINCS, a post-quantum signature scheme combining stateless (Sphinx-based) and stateful (hash-based) components for Bitcoin.
- Hash-based signatures offer conservative cryptographic assumptions compared to elliptic-curve cryptography, providing resilience against multiple threat vectors beyond quantum computers.
- SHRINCS uses WOTS+C (Winternitz one-time signatures with compression), FORS (Forest of Random Subsets), and XMSS (Extended Merkle Signature Scheme) as its core building blocks.
- The scheme introduces flexible tree structures (unbalanced and balanced XMSS) for different use cases, enabling address reuse for custodians and proof-of-reserve scenarios without sacrificing security.
- Stateful signatures are ~538 bytes versus stateless signatures at ~5,776 bytes, both roughly 10x larger than current Schnorr signatures, with faster verification offsetting size concerns.
- State management remains the critical risk: wallet developers must carefully track signature counters to avoid accidental key exposure through signature reuse.