What Is a Public Key?
A public key is a publicly shareable cryptographic key associated with a private key, used for verifying digital signatures within a cryptographic network.
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What Is a Public Key?
A public key is information used to verify digital signatures created with a private key. It is mathematically derived from the private key. In secure cryptographic systems, it should be practically impossible to find the private key by knowing the public key.
When you sign a transaction, the network verifies that you have the authority to spend through this key relationship. You do not need to send the private key itself to the network. This way, while anyone can check the signature, only the person holding the key can create a valid signature.
Is a Public Key the Same as an Address?
Generally, no. A wallet address may be a different representation created from the public key or a spending condition, depending on the rules of the respective network. In Bitcoin, not all address types are simply the representation of a single public key. Therefore, when a platform asks for a “recipient address,” pasting the public key is not the correct procedure.
For example, you use the shareable address seen in the “Receive” section of the wallet. The long public key field encountered in developer tools may not substitute for the daily receiving address. The application’s own instructions determine which format is required.
What Information Does Sharing Reveal?
A public key does not directly grant spending authority; however, unnecessary sharing can have privacy implications. In particular, the extended public key, or xpub, can allow for the derivation of numerous addresses and the tracking of movements in some wallets. It can create broader visibility than sharing a single address.
Giving an xpub to a tracking app just to show a balance is not the same as giving a private key. While the former cannot spend funds, it can reveal a significant portion of your transaction history. Do not accept the term “read-only” as a full privacy guarantee without understanding what information the wallet is exporting.