What Is A Bitcoin Address

A Bitcoin address is derived from the public key — another layer of the same one-way mathematical process. It’s the string of letters and numbers you share when you want to receive Bitcoin.

The mailbox analogy is accurate. An address is a location on the Bitcoin network where value can be sent. Anyone who knows the address can send Bitcoin to it. Only the person who holds the corresponding private key can spend from it.

A few things worth understanding about addresses.

They’re designed to be shared. Unlike a private key — which should never be shared — a Bitcoin address is meant to be given out. Posting it publicly is fine. Sharing it in an email is fine. Printing it on a business card is fine. Nobody can steal your Bitcoin by knowing your address. They can only send you more.

They should ideally be used once. Most modern wallets generate a new address for every incoming transaction. This is a privacy feature — reusing the same address allows anyone to connect your transaction history by searching the public blockchain. A fresh address for each transaction makes that linking harder.

They’re shorter than public keys. Public keys are long and unwieldy. Addresses apply additional processing to produce something more manageable — and include a checksum that catches typos before a transaction is sent.

The chain from private key to public key to address is the foundation of how Bitcoin ownership works. The private key stays hidden. The public key proves the private key exists. The address receives the funds. All three are mathematically linked — and none of them require trusting anyone.

Tomorrow: what is cryptography — the lock that secures the whole system.

— The Daily Bit