Public Key vs. Private Key
Last reviewed: August 2026
People say "key" like it's one thing, so what actually separates the public one from the private one? Picture a mailbox: the address on the front is public, and anyone can drop mail into it, but only the matching physical key can open the box and take mail out. A private key works like that physical key: it authorizes taking action. A public key, or the address derived from it, works like the mailbox address, meant to be shared so others know where to send something.
Private Key vs. Public Key
| Dimension | Private Key | Public Key |
|---|---|---|
| Role | The secret credential that proves you can move funds: spending authorization. | Derived mathematically from the private key, used to receive funds, not authorize sending them. |
| Secrecy | Must stay secret. Anyone else who gets it can act as if they were you. | Safe to share. Publishing it doesn't reveal the private key it came from. |
| If Exposed | Full compromise: if it leaks, everything it protects is exposed along with it. | No compromise: it's already meant to be public. |
The distinction is simple once stated plainly: the private key authorizes, the public key receives, and only one of the two needs to stay secret. Read more in Key Security.