HRP and Separator

The most visible difference between a legacy address and a SegWit address is the "Header." In Bech32, this is formally divided into the Human-Readable Part (HRP) and the Separator.

1. The HRP (Human-Readable Part)

The HRP tells the user and the software which network the address belongs to.

• bc: Main Bitcoin Network (Mainnet).

• tb: Bitcoin Testnet.

• bcrt: Bitcoin Regtest (Local development).

This is a major improvement over Base58. In the legacy system, you had to decode the entire address just to find the "Version Byte" to see if it was a Testnet address. In Bech32, you can tell just by looking at the first two letters.

2. The Separator ('1')

The character 1 serves as a "Wall" between the human-readable network ID and the encoded cryptographic data.

• The separator is Always the character 1.

• Because 1 is excluded from the Base32 data alphabet, the computer knows that the very first 1 it sees marks the end of the HRP.

3. Why '1'?

The character 1 was chosen as the separator because it is visually distinct and rarely occurs at the start of a network name. It provides a clear visual break for the human eye, separating the "Where" (Network) from the "Who" (Encoded Hash).

4. Verification Logic

When a wallet parses bc1qar0s...:

1. It finds the last 1 in the string.

2. Everything to the left is the HRP (bc).

3. Everything to the right is the Data Part.

4. If the HRP is bc, the wallet knows this transaction is intended for the Mainnet. If you try to send Mainnet funds to a tb1... address, the wallet will stop you immediately.

Network	HRP	Example
Mainnet	bc	bc1q...
Testnet	tb	tb1q...
Signet	tb	tb1q...

In the next section, we will analyze the Bit Grouping (5-bit chunks) process.