PGP Desktop has the only true "this message will self-destruct" feature, as far as I've seen.
PGP encrypted messages. Opened in a secure viewer. No copy and paste. No easy screenshotting (dx10 overlay if I'm not mistaken - bypassable, of course, but decent anyway). Close it and it's gone.
PGP encrypted messages. Opened in a secure viewer. No copy and paste. No easy screenshotting (dx10 overlay if I'm not mistaken - bypassable, of course, but decent anyway). Close it and it's gone.