Blockstream Proposes SHRINCS Post-Quantum Signature Scheme for Bitcoin

Blockstream proposes a post-quantum signature system designed for Bitcoin $BTC. Standard post-quantum signatures standardized by NIST drop Bitcoin $BTC throughput from 6.5 to 0.36 transactions per second. Blockstream's SHRINCS proposal maintains roughly 3 transactions per second with signatures starting at 324 bytes. The scheme relies on SHA-256 hashes, but requires wallets to track fresh one-time keys per transaction across backups and hardware devices. Bringing the proposal to mainnet would require a backwards-compatible soft fork. "the first concrete post-quantum signature proposal designed specifically for Bitcoin." — Jonas Nick Mitigating throughput degradation is necessary, but stateful one-time keys introduce serious state-tracking complications for offline cold storage.