Glossary

Public Key

Plain-language definition Crypto glossary

Key takeaways

A public key is a cryptographic value derived from a private key that can be shared freely and is used to receive funds and to verify signatures.
Public-key cryptography uses a key pair where the private key signs and the public key verifies, and a wallet address is typically a shortened, encoded form of the public key.
Sharing a public key or address is safe, while sharing a private key is not, because the relationship between them only works in one direction.

Definition

A public key is a cryptographic value derived from a private key. It can be shared freely and is used to receive funds and to let others verify that a transaction was genuinely signed by the matching private key.

How it works

Public-key cryptography uses a pair of keys. The private key signs; the public key verifies. A wallet address is typically a shortened, encoded form of the public key. When you receive crypto, the sender is sending it to an address derived from your public key; when you spend, the network checks your signature against that public key to confirm you are authorised.

Why it matters

This one-way relationship is what makes blockchains trustless: you can prove ownership and authorise transfers without ever revealing the secret that controls your funds. Sharing a public key or address is safe; sharing a private key is not.

Example

The address you paste into an exchange’s “withdraw” field is generated from your wallet’s public key.

FAQ

Frequently asked questions

Is it safe to share my public key or address?

Yes. The public key and the address derived from it are meant to be shared so others can send you funds and verify your signatures. The one-way relationship means no one can work backward from your public key to the private key that controls your funds.

What is the difference between a public key and a wallet address?

A wallet address is typically a shortened, encoded form of the public key, designed to be easier and safer to share. They are closely related, and funds you receive are sent to the address derived from your public key.

How do public and private keys work together?

The private key signs a transaction and the public key verifies that signature. This lets you prove ownership and authorise transfers without ever revealing the secret private key, which is what makes the system trustless.