Bitcoin Addresses

You may have seen people on the Internet posting their Bitcoin address. A Bitcoin addresses is randomly generated by your Bitcoin software, and is given to others so they may send you a payment, similar to how you give out your email address to receive email. An address is usually 33-34 characters long, and always starts with the number “1” (or “3”, for a newer type of address which requires two or more parties to consent when sending).

An address cannot be mistyped, as input errors are detected as invalid addresses. Instead of typing though, most users will be cut-and-pasting on computers, or scanning address QR codes, due to an address’s length.

An address is actually made of two parts – the public address that is safe to give to anyone, and a corresponding secret part used behind the scenes by Bitcoin software when sending a payment. Only an address’s owner can send a payment from an address, because only an owner’s wallet contains the secret private key.

㋔ Geek Facts

An address is an Elliptic Curve Digital Signature Algorithm public/private key pair. The actual address that is shared with others is a cryptographic hash of the public key, encoded in a human-readable format called Base58.

A private key can sign messages, creating a signature that could only be created by the owner, which others can verify when they are given the public key. Bitcoin uses this technology to prove individual payments are authorized by the owner.

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