csfieldguide/chapters/content/en/glossary/public-key-cryptography.md
# Public key cryptography
A system where a *public key* can be safely broadcast to anyone, but messages encrypted with it can only be read by a secret *private key*.
This is known as an *asymmetric* system, because you don't use the same key to encrypt and decrypt a message.
Similarly, messages decrypted with the public key could only have been encrypted with the private key.
This can be used to prove a message was sent by the intended sender, and not a third party with malicious intent.