I'm also interested in this topic. Thawte AFAIK doesn't provide a dedicated certificate for Java apps. This also applies to other CAs like verizon. Can a regular SSL certificate for a web server be used. If yes, what's with the "lifetime" of such a certificate? When I sign my MIDlet with a certificate for one year, will devices notice when I install this MIDlet after the year, so that I have to rebuy the certificate and put a new version online?