Blockstream Publishes BIP for Post-Quantum Signature Scheme SHRINCS
Blockstream has published a Bitcoin Improvement Proposal (BIP) for its experimental post-quantum signature scheme, SHRINCS. This move comes as the company acknowledges the threat of quantum computers to Bitcoin's security.
The BIP is significant because it provides a concrete proposal for upgrading Bitcoin's elliptic-curve signature system, which is vulnerable to key-recovery attacks by powerful quantum machines. While the exact timeline for this threat is debated, cryptographers agree that allowing attackers to derive private keys from public keys and steal funds would be catastrophic.
The SHRINCS design is notable for being 'Bitcoin-native' and smaller than many NIST-aligned post-quantum signature alternatives. However, it introduces wallet/device recovery and interoperability risks due to its stateful approach. Blockstream's ongoing research explores complementary ideas, including signature-size reduction and potential ZK proof aggregation.
The company has previously demonstrated SHRINCS on Liquid, a Bitcoin sidechain, and the new BIP frames this experimental work for Bitcoin improvement discussions. Jonas Nick, a Blockstream Research researcher, characterized the BIP as 'the first concrete proposal' for a post-quantum signature scheme built specifically around Bitcoin's needs.