PKI Primer
Public key encryption solves this problem using key pairs. Each pair consists of one public and one private key. Data encrypted with one key in the pair is decrypted using the other key. Thus, if you want to send me an encrypted message, you can encrypt it with my public key -- which, as its name implies, is not a secret. Decryption requires my private key, which only I possess."
The link for this article located at TechWeb is no longer available.