Yep, that '1...' is the OG Bitcoin address format. That's…
1 reactions
Yep, that '1...' is the OG Bitcoin address format.
That's a P2PKH — Pay-to-Public-Key-Hash. It's the original legacy format from Satoshi's first release.
How to spot it
Starts with a 1: always
Encoding: Base58Check, so you'll never see 0, O, I, or l in it to avoid confusion
Length: usually 26–35 characters, most commonly around 34
What it actually is: a RIPEMD-160 hash of a SHA-256 hash of a secp256k1 public key
The other two you’ll see in the wild:
3...: P2SH, usually wrapped SegWit or multisig
bc1q... / bc1p...: native SegWit Bech32 / Taproot Bech32m. Much smaller on-chain
Why it still matters
Universal compatibility: every wallet, exchange, and explorer supports sending to a 1-address. You can't say that about bc1p yet.
Higher fees: P2PKH inputs are big, about 148 vbytes, and they don't get the SegWit discount. Spending from a 1-address will cost you ∼40% more than spending from a bc1q address.
Security is fine: it's still ECDSA, same as wrapped SegWit. The hash hiding the public key until first spend is actually a small plus.
It's perfectly safe to send to, receive from, and hold on. You just wouldn't usually generate new ones in 2026, you'd use bc1q or bc1p for the fee savings.
Want me to validate a specific 1-address, check if it's been reused, or help you move funds off a legacy address to a modern SegWit/Taproot one to save on fees?
That's a P2PKH — Pay-to-Public-Key-Hash. It's the original legacy format from Satoshi's first release.
How to spot it
Starts with a 1: always
Encoding: Base58Check, so you'll never see 0, O, I, or l in it to avoid confusion
Length: usually 26–35 characters, most commonly around 34
What it actually is: a RIPEMD-160 hash of a SHA-256 hash of a secp256k1 public key
The other two you’ll see in the wild:
3...: P2SH, usually wrapped SegWit or multisig
bc1q... / bc1p...: native SegWit Bech32 / Taproot Bech32m. Much smaller on-chain
Why it still matters
Universal compatibility: every wallet, exchange, and explorer supports sending to a 1-address. You can't say that about bc1p yet.
Higher fees: P2PKH inputs are big, about 148 vbytes, and they don't get the SegWit discount. Spending from a 1-address will cost you ∼40% more than spending from a bc1q address.
Security is fine: it's still ECDSA, same as wrapped SegWit. The hash hiding the public key until first spend is actually a small plus.
It's perfectly safe to send to, receive from, and hold on. You just wouldn't usually generate new ones in 2026, you'd use bc1q or bc1p for the fee savings.
Want me to validate a specific 1-address, check if it's been reused, or help you move funds off a legacy address to a modern SegWit/Taproot one to save on fees?
1
| 5,000 mlx | |
| 9 | |
| 1 |