Trying to folow on from DaveRo... https (tls/ssl) of course does use certificates but this is for a client (eg. browser) to establish that the remote server is genuine. You can, as I sort of mentioned in an earlier post, "self sign" a certificate but it's not likely to have any use outside your own network. Browsers will pop up warnings that the certificate isn't trusted, or similar. Unless you know what you are doing (eg. something on your own network you have set up), heed the warning and don't visit the site.