A private key is a long secret number that gives access to crypto. It works like the key to a safe deposit box: whoever has the key can take what is inside.
How does a private key work?
Every crypto walletCrypto walletAn app or device that holds the keys to your crypto and lets you receive, store and send it. is built on a key pair. The private key is your secret. A public keyPublic keyA key calculated from your private key that others use to verify your signatures, and that is safe to share. is calculated from it, and from the public key comes the wallet addressWallet addressA string of letters and numbers you give out to receive crypto, much like a bank account number. you give people so they can send you crypto.
When you send crypto, your wallet signs the transaction with the private key. Anyone on the network can check that the signature is valid without ever seeing the key itself. This is made possible by CryptographyCryptographyMathematical methods that protect information and prove who sent it, forming the basis of security in crypto..
A private key can look like this, a 64-character string:
e9873d79c6d87dc0fb6a5778633389f4453213303da61f20bd67fc233aa33262
Most wallets never show you the key itself. Instead you get a seed phraseSeed phraseA list of 12 or 24 words that backs up every key in your wallet, so whoever has the words can restore the wallet and take the crypto., 12 or 24 ordinary words from which your keys are derived.
Why does it matter?
If you lose your private key and don't have your seed phrase, nobody can help you recover the crypto. If someone else gets hold of it, they can take everything in the wallet, and the transaction can't be reversed.
So:
- Never share your private key or seed phrase with anyone. No legitimate service will ask for them.
- Keep them somewhere safe, preferably not on your phone or in your email.
When you keep crypto with a CustodianCustodianA company that holds crypto and the keys to it on behalf of customers, such as a licensed crypto exchange., such as a crypto exchange, the custodian manages the keys for you. With Self-custodySelf-custodyHolding the private keys to your crypto in your own wallet, so nobody else controls it but all the responsibility for the keys is yours., the responsibility is yours.
Everything in Myntkaup Learn is written and regularly reviewed by the Myntkaup editorial team. It is for education and is not investment advice. Editorial policy. Updated 18 October 2026.