If you set things up properly, you could be granted 20 public keys and one single boilerplate e-mail containing everybody's grades, with each one encoded in the

If you set things up properly, you could be granted 20 public keys and one single boilerplate e-mail containing everybody's grades, with each one encoded in their appropriate key. Everybody would then attempt to decode each cipher, with only one working for any individual private key. This isn't all that different from your original posting, except that you now only need to send one unique e-mail. (For Beavis, who's getting an F because he never showed up to class, you might get in trouble with the administration because a simpleton couldn't decode their grade through this or other sophisticated means.)