Im unsure of what you are describing. Are you stating that hotmail should be able to display your decrypted emails? That would imply that they themselves would be able to read it and therefore remove any benefit. Any website you would build would have the same problem unless you resort to js crypto in which the js can be changed on you in a second (when the government forces your company to do so) and send the private key to the nsa. How exactly are you envisioning a solution?