# Managing Public and Private Keys

A public key is contained in a certificate. Since the certificate represents public key information, it is published. When distributing the public key to other users, you may e-mail it as a signed mail message, export the certificate to a file and then distribute it, or use a directory server.
When exporting a certificate to a file, you can export it using a private key if you are the named individual. But such exporting would result in a file that contains a private key at the same time, thus requiring care in handling.
A private key is information that should be known only to its owner, and it must be securely managed on his / her own responsibility. Since your private key cannot be restored once lost, it is recommended that you make a backup copy of it and keep it in a safe place. In case you lost your private key, you cannot open those DocuWorks documents to which security has been set using the corresponding certificate or cancel the security of them any longer.