P2WSH ScriptPubKey Structure

The P2WSH locking script is a Witness Program for complex logic. Like P2WPKH, it is minimalist and uses versioning, but it is larger because it stores a 256-bit cryptographic hash.

1. The Locking Script (ScriptPubKey)

A P2WSH script is exactly 34 bytes long: 00 20 [32-Byte SHA256 Script Hash]

• 0x00: The Witness Version (Version 0).

• 0x20: The push-data opcode for 32 bytes (hex 0x20).

• [32-Byte Hash]: The SHA256 hash of the full multisig script (the Witness Script).

2. P2WPKH vs. P2WSH Length

It is very easy to tell the difference between a single-key and a multisig native SegWit output just by looking at the raw hex length:

• P2WPKH: Starts with 0014... (22 bytes total).

• P2WSH: Starts with 0020... (34 bytes total).

3. SHA256 Directness

In P2SH, the 20-byte hash is a "Double Hash" (SHA256 then RIPEMD160). In P2WSH, the 32-byte hash is a Single SHA256.

• This simplifies the mathematical verification process for nodes.

• By using a 256-bit hash, Bitcoin ensures that even if one day computers become fast enough to crack 160-bit hashes, your multisig funds will remain secure.

4. The "No Opcodes" Rule

Just like in P2WPKH, there are no opcodes like OP_EQUAL in the ScriptPubKey. The node knows that because it is a 0020 script, it MUST hash the provided witness data and check for equality. This hardcoded logic saves space and prevents potential script-injection bugs.

Attribute	P2WPKH	P2WSH
Push Opcode	0x14 (20 bytes)	0x20 (32 bytes)
Data Type	Public Key Hash	Witness Script Hash
Total Script Size	22 Bytes	34 Bytes
Address Length	42 chars	62 chars

In the next section, we will examine the Witness Stack for P2WSH.