Pay-to-Witness-Script-Hash (P2WSH)

Pay-to-Witness-Script-Hash, or P2WSH, is the native SegWit output type for script-controlled coins, the successor to P2SH. It commits to the SHA-256 hash of a script, 32 bytes rather than P2SH's 20, and its bech32 addresses begin with bc1q but are longer than single-key SegWit addresses. Multisig arrangements are its dominant use.

Why it matters

The 32-byte commitment closed a theoretical weakness in P2SH, whose 20-byte hash offers only 80 bits of collision resistance, marginal for high-value scripts where an attacker participating in script construction could try to engineer collisions. P2WSH restores a full 128-bit security level. As a witness-native format it benefits from the block weight discount, so complex scripts spend more cheaply than their P2SH equivalents, and it inherits malleability protection, which matters for protocols chaining unconfirmed transactions, including Lightning channel funding, built on 2-of-2 P2WSH multisig.

In the gold vs bitcoin debate

P2WSH is quiet infrastructure beneath institutional bitcoin custody: much of the collaborative custody and exchange cold storage built between 2017 and the Taproot era rests on it. In the comparison with gold, it belongs to the same argument as its siblings, that authority over bitcoin can be divided, conditioned and enforced by mathematics, where dividing authority over gold requires dividing trust.