Essentially, a Bitcoin wallet private key is like a password required to access and manage the Bitcoin stored in your wallet. To send Bitcoin from your wallet to another, you need your wallet’s private key to confirm the transaction. A Bitcoin wallet has both a public and private key. A public key is like a social media username, which you can share with other users and is publicly visible. A private key is like the social media account password — it’s needed to access and manage the account.