P2WPKH: Native SegWit (The bc1q Addresses)

P2WPKH (Pay-to-Witness-Public-Key-Hash) is the native SegWit standard for single-signature accounts. It represents the "Clean" implementation of the 2017 SegWit upgrade, removing the legacy P2SH wrapper and moving directly to a more efficient address format called Bech32.

1. The Pure SegWit Experience

Unlike Nested SegWit, which hides inside a legacy "3" address, Native SegWit addresses start with bc1q.

• No Overhead: It removes the unnecessary 22-byte Redeem Script from the ScriptSig.

• Max Efficiency: Because it has the least amount of "Base Data," it is the cheapest single-key script type to spend.

2. Why "Native"?

It is called "Native" because the locking script itself is written in the new SegWit versioning format. The blockchain doesn't have to perform a hash check on a wrapper; it knows immediately that the output is a SegWit Version 0 output.

3. The Bech32 Revolution

P2WPKH introduced a completely new way of writing addresses:

• Lowercase Only: No more confusing O vs 0 or I vs l.

• Error Detection: It uses a sophisticated checksum that can detect and even locate multiple errors in a typed address.

• QR Code Friendly: Because it uses only lowercase letters and numbers, QR codes are much smaller and easier for cameras to scan.

4. Adoption Timeline

While Native SegWit was technically superior in 2017, it took several years for the industry (exchanges, hardware wallets, and block explorers) to fully support sending to bc1q addresses. Today, it is the industry standard for modern Bitcoiners.

Feature	Legacy (P2PKH)	Native SegWit (P2WPKH)
Address	Starts with 1	Starts with bc1q
Encoding	Base58Check	Bech32
Spending Fee	100% (Baseline)	~60% (Discounted)
ScriptSig Size	~100 Bytes	0 Bytes

In the next section, we will analyze the ScriptPubKey Structure of P2WPKH.