You received some crypto from your friend, which is now showing up as a balance in your wallet app. What's the nature of that "balance"? The blockchain miners crediting your account with a positive balance at the request of your friend The on-chain record that your address has received crypto from your friend's address has been accessed by your wallet and displayed as balance Your wallet received an incoming connection and transfer from your friend's wallet Your private key has been authorized by your friend to initiate a pull transaction from his/her address