Bitcoin's Quantum Defense Gets a Boost with SHRINCS Draft
A team of researchers has published a draft specification for SHRINCS, a post-quantum signature scheme designed to protect Bitcoin transactions from potential quantum computer threats.
The proposal aims to reduce the burden on block space by providing two signing paths for each public key, with the compact stateful component FXMSS producing signatures ranging from 548 to 4,619 bytes and a larger stateless fallback having a fixed signature size of 5,777 bytes.
The draft targets NIST security category 1, corresponding to 128 bits of classical security and 64 bits of quantum security, relying on the SHA-256 hash function's security. The authors argue that this approach is conservative and valuable for Bitcoin due to its long-lived unspent outputs.