Address
A crypto address is the destination you hand out to get paid — a shortened, error-checked form of your public key.
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An address is the string a sender pays to. In Bitcoin it is usually a hashed public key encoded with a checksum that catches typos [1]; on Ethereum it is the last 20 bytes of the Keccak-256 hash of the public key, with “0x” in front [2].
Key points
- 1Safe to share: an address cannot be reversed into your private key.
- 2Built-in checksums catch most typing mistakes before money is sent.
- 3Every address is public on the blockchain, so reusing one links your payments together.
How is an address made?#
Your wallet starts with a private key, derives a public key from it, then hashes the public key. The hash shortens the key and adds protection against unforeseen attacks on public keys; it is then encoded with a version number and an error-detecting checksum so it is easy to copy without mistakes [1]. The Bitcoin developer glossary describes a classic address as a 20-byte hash formatted with base58check [3].
| Step | Value |
|---|---|
| “bc” | Human-readable part: Bitcoin mainnet (testnet uses “tb”) |
| “1” | Separator between the label and the data |
| The characters after “1” | The encoded data, using an alphabet without “1”, “b”, “i” or “o” |
| The last 6 characters | Checksum: detects any error in up to 4 characters |
An Ethereum address works differently: 20 bytes written as 40 hexadecimal characters plus “0x”, so 42 characters in total [2].
Is an address the same as a public key or a wallet?#
No. The address is derived from the public key but is not the key itself, and a wallet is the software that stores your keys and can manage many addresses. bitcoin.org adds a privacy reason to use each address only once: anyone can see the balance and transactions of any address [5]. The full picture is in public keys, private keys and addresses.
Which words are related?#
- Private key — the secret behind the address.
- Seed phrase — words that can regenerate all of a wallet’s keys and addresses.
- UTXO — the unspent outputs locked to Bitcoin addresses.
Frequently asked questions#
Can someone steal my crypto if they know my address?
No. An address only lets people send to you and view its public history. Spending needs the private key.
Why does my wallet keep showing new addresses?
Reusing an address makes it easy to track your payments, so wallets generate fresh ones for privacy [1]. Old addresses keep working.
Can I send Ethereum to a Bitcoin address?
No. The formats are different and belong to different networks. Always match the asset and network to the address type.
Sources#
Grade A = primary source (regulator, protocol specification, client code, original author). Grade B = expert secondary source used for explanation only.
- Abitcoin.org developer documentation. Developer Guide: Transactions, 2026.
- Aethereum.org. Ethereum accounts, 2026.
- Abitcoin.org developer documentation. Bitcoin Developer Glossary, 2026.
- ABitcoin Improvement Proposals (GitHub). BIP 173: Base32 address format for native v0-16 witness outputs, 2017.
- Abitcoin.org. Some things you need to know, 2026.