Blockstream Proposes SHRINCS Quantum-Resistant Signature Scheme for Bitcoin

Blockstream has introduced a Bitcoin Improvement Proposal (BIP) for SHRINCS, a hash-based post-quantum signature scheme. While the signature size is 548 bytes—approximately nine times larger than current Schnorr signatures—it remains significantly more compact than NIST-approved alternatives like ML-DSA and SPHINCS+. The scheme has undergone production testing on the Liquid sidechain. However, the proposal notes limitations, including the need for further security verification and the stateful nature of the system, which requires tracking used keys and incr