HTTPS is a protocol used to provide security over the Internet. HTTPS guarantees that users are talking to the server they expect, and that nobody else can intercept or change the content they’re seeing in transit.
If you have anything that your users might want private, it’s highly advisable to use only HTTPS to deliver it. That of course means credit card and login pages (and the URLs they submit to) but typically far more of your site too. A login form will often set a cookie for example, which is sent with every other request to your site that a logged-in user makes, and is used to authenticate those requests. An attacker stealing this would be able to perfectly imitate a user and take over their login session. To defeat these kind of attacks, you almost always want to use HTTPS for your entire site. That’s no longer as tricky or expensive as it once was. Let’s Encrypt provides totally free and automated certificates, which you’ll need to enable HTTPS, and there are existing community tools available for a wide range of common platforms and frameworks to automatically set this up for you. Notably Google have announced that they will boost you up in the search rankings if you use HTTPS, giving this an SEO benefit too. Insecure HTTP is on its way out, and now’s the time to upgrade.
