Pay-to-Witness-Public-Key-Hash (P2WPKH)

Pay-to-Witness-Public-Key-Hash, or P2WPKH, is the native SegWit version of the standard single-key output, introduced when Segregated Witness activated in August 2017. Its addresses use bech32 encoding and begin with bc1q. Signature data moves into a separate witness section that receives a 75 percent discount in block weight accounting, making P2WPKH spends roughly 30 to 40 percent cheaper than legacy equivalents.

Why it matters

Moving signatures to the witness fixed transaction malleability, the ability of third parties to alter a transaction's ID before confirmation, which had complicated protocols built on unconfirmed transactions and blocked the Lightning Network's design. The witness discount also increased effective block capacity without a hard fork. For users the visible effect is fees: the same payment costs meaningfully less than from legacy addresses, and bech32 addresses are case-insensitive with robust error detection, reducing transcription mistakes. By 2023 a clear majority of bitcoin transactions were spending SegWit outputs.

In the gold vs bitcoin debate

P2WPKH's rollout demonstrated how bitcoin's economy adopts upgrades voluntarily: exchanges and wallets migrated over years as fee savings justified the engineering work, with no authority able to force the change. It also cleared the path for Lightning, the layer carrying bitcoin's medium-of-exchange case, a kind of self-improvement physical gold's fixed nature never permitted.