Public key vs private key
What is a public key and a private key?
Public key and private key are the two unique codes that sit behind every crypto wallet. The private key is secret and proves you own the funds. The public key comes from that private key, through a one-way process, and you can give it out without risk.
This setup uses asymmetric cryptography. When you sign a transaction with your private key, anyone can verify the signature with your public key, but nobody can guess the private key by looking at the public one. Your wallet program creates the pair automatically, usually from a random input, which means you rarely see these numbers directly. For the whole structure, check how wallets work.
How keys create addresses and sign transactions
Your wallet address is a shorter code, produced by hashing (one-way scrambling) your public key. This address is what you show others, they use it to send you coins. There is no danger in sharing it.
When you send coins, the wallet software uses your private key to make a digital signature for this transaction. The crypto network checks this signature with the public key. If those match, the transfer goes through. At no point is your private key given out to the network. If you want more technical details, see crypto wallet addresses.
Why sharing a private key means giving away your funds
If someone discovers your private key, they can transfer your coins out, with no further permission needed. There's no bank helpdesk here, usually, there's no one to reset a key or undo a transaction. Don't paste your private key into online forms, don't send it by message, and don't hand it over to anyone pretending to offer help.
Some wallet apps show keys or backup phrases as series of random words or letters. Treat every version of these details as confidential. Crypto can be high-risk, prices can swing, and losing your key is losing your money. To see how these backup phrases relate to your keys, read our article about the seed phrase.
Frequently asked questions
Is a public key the same as a wallet address?
No, they're not. Wallet addresses are generated from public keys, using a hash to make them more compact and to add error-checking. You share your address when you want to get paid. The public key is used under the hood for transaction verification.
Can someone find my private key from my public address?
No, they can't. The encryption tools behind crypto are built specifically so that a private key isn't recoverable from a public key or address. The bigger risk is your own key or backup phrase getting leaked because of phishing attempts, viruses or poor storage choices; always store sensitive details offline and never share them.