There's pretty good evidence that you should not trust your ISP: http://www.theverge.com/2013/7/21/4541342/isp-owner-describes-nsa-box-that-spied-on-customers

There's pretty good evidence that you should not trust your ISP: http://www.theverge.com/2013/7/21/4541342/isp-owner-describes-nsa-box-that-spied-on-customers http://www.theverge.com/2013/7/21/4541342/isp-owner-describe... While your message contents would still be encrypted when using the regular old ProtonMail site, it would expose your identity and who you are sending messages to.