As technology development to address the quantum-computer threat to Bitcoin gathers momentum, P2MR and SHRINCS are emerging as leading candidates.
BIP-360, currently at the draft stage, proposes a new output type called Pay to Merkle Root (P2MR). P2MR aims to reduce the risk of “long-exposure” quantum attacks, in which public keys remain exposed for an extended period, by removing Taproot’s key-path spending function and using a script tree.
Blockstream Research is separately developing SHRINCS, a SHA-256-based post-quantum signature scheme. SHRINCS generates 324-byte signatures in its stateful mode and also provides a stateless recovery path in case state information is lost.
In March 2026, Blockstream processed an actual post-quantum signature transaction using SHRINCS on the Liquid Network. It is also developing a separate BIP draft for deployment on the Bitcoin mainnet.