Thanks for the hint, but I really don't wanna use a non secured connection to deal with my money... But at least I can enter the site now, maybe I'll be able to contact some support.
The connection
is secured, but the SSL certificate expired yesterday and StrongCoin has yet to renew it, which is... highly improper, but not at all unusual. Many financial institutions allow their SSL certificates to expire, and their users in most cases simply ignore their browser's warnings. I don't know which is more stupid. Either way, I would advise against using StrongCoin until they renew their certificate.