A cryptographic key derived from a private key that can be shared openly. In Bitcoin, public keys are used to generate addresses and verify that transactions were authorized by the corresponding private key holder.
A cryptographic key derived from a private key that can be shared openly. In Bitcoin, public keys are used to generate addresses and verify that transactions were authorized by the corresponding private key holder.
A public key is one half of a cryptographic key pair used in Bitcoin's elliptic curve cryptography (specifically, the secp256k1 curve). Every Bitcoin private key has a corresponding public key, derived through a one-way mathematical function. While the public key can be freely shared, it is computationally infeasible to reverse-engineer the private key from it.
In Bitcoin's transaction model, public keys serve as identity and verification. When you send Bitcoin, your wallet creates a digital signature using your private key. The network verifies this signature using your public key, confirming that you authorized the transaction without ever seeing your private key. This is the fundamental mechanism that makes Bitcoin secure — you prove ownership without revealing your secret.
Bitcoin addresses (the strings you share to receive payments) are derived from public keys through hashing. This adds an extra layer of security: even if elliptic curve cryptography were somehow broken, an attacker would still need to reverse the hash to go from an address to a public key. Modern address formats (P2WPKH, P2TR) only reveal the public key when you spend from an address, not when you receive to it.
A public key is the raw cryptographic key derived from your private key. A Bitcoin address is created by hashing the public key (using SHA-256 and RIPEMD-160) and encoding the result. The address is shorter, includes a checksum to prevent typos, and provides an additional security layer. You share your address to receive Bitcoin; the public key is revealed to the network only when you spend from that address.
Yes, sharing your public key is safe — it is designed to be public. There is no known way to derive a private key from a public key using current or foreseeable technology. However, best practice is to share your Bitcoin address rather than the raw public key, as the additional hashing provides defense-in-depth against potential future advances in cryptography, including quantum computing.
When you create a transaction, your wallet signs it with your private key, producing a digital signature unique to that transaction. Anyone with your public key can mathematically verify that the signature was produced by the corresponding private key — but they cannot determine what that private key is. This allows the entire network to verify your authorization without you ever revealing your secret.