Public key
TL;DR
A public key is a cryptographic key derived from the private key, used to verify transactions and generate Bitcoin addresses.
The public key is the public counterpart of the private key — freely shareable without risk. From it, others compute your Bitcoin address and verify signatures made with your private key. There's no way to reverse-engineer the public key back to the private key (one direction trivial, the other infinitely hard).
Example
During a tx your public key is revealed (in some address types) or only its hash. Others verify the signature without ever seeing your private key — asymmetric cryptography's magic.
Frequently asked questions
Is my Bitcoin address the same as my public key?
No, but derived. Address = hash of public key, sometimes encoded in bech32 (bc1...). The extra hash adds quantum-resistance.
Related terms
Further reading
- → Our service: Bitcoin sector