Blockstream Research Unveils Quantum-Resistant Signature Scheme Library
Bitcoin developers at Blockstream Research have made a significant step towards post-quantum security with the release of libshrincs, a proof-of-concept library for quantum-resistant signature schemes. Libshrincs implements WOTS+C, one component of the SHRINCS scheme, which blends stateful and stateless hash-based signatures to keep signature sizes compact while providing quantum resistance.
The project is notable not just for what it protects against, but also for how it was built. Large language models like ChatGPT and Fable were used to generate substantial portions of the verification code under human oversight. This marks a significant attempt to formally verify cryptographic code meant to shield Bitcoin from powerful quantum computers.
The library ships with machine-checked proofs of functional correctness and security, verified using SSProve in Rocq. The proofs are substantial: approximately 6,200 lines of VST code and around 13,400 lines of Rocq code.