PrivateKeyFile defines a private key file name in name=value,filename format. This key is used when an encrypted permanent identity sent by the client has a key identifier. Decryption is attempted only with the key that matches the key identifier the client sends. If the key is not able to correctly decrypt the encrypted identity, an error is returned to the client and the authentication fails. You should not configure more than one PrivateKeyFile parameter with the same name=value because only the latest parameter is used.