HTTP or Hyper Text Transfer Protocol is "the foundation of data communication for the World Wide Web."
HTTPS is a protocol that does the job of HTTP with an added layer of security, by enabling encrypted communication of the data between your browser and the website. It used to only be commonplace on sites that dealt with confidential data when purchasing something online or logging in to a site, but times they are a changin'.
HTTPS shows the authentication of the website for the "protection of the privacy and integrity of the exchanged data." One can easily get lost in the technical side of how this works, but simply put:
HTTPS is the encrypted secure version you want to see on websites you visit.
Our HTTPS certificate was issued from Let's Encrypt. It uses TLS 1.2 and the "connection is encrypted and authenticated using AES_128 GCM and uses ECDHE_RSA as the key exchange mechanism." Here is more information than you need on TLS 1.2 from the Internet Engineering Task Force (IETF).
Let's Encrypt enables any webmaster the ability to incorporate a free certificate on their site for safer browsing for their users. This follows suit of the broad and attainable goal that Access Now and Encrypt All The Things are aiming for, an entirely encrypted and safe internet. If you have any further questions about HTTPS or how to implement, the developers that helped create this website will be happy to assist.
Users can usually know they are securely browsing on a website when they see the HTTPS in the URL. Having HTTPS incorporated can stop Man-in-the-middle (MITM) attacks (Blackhat - PDF 1, 2) and protect from eavesdropping or tampering of the communication data. You can also force non HTTPS sites to utilize the protocol through the add-on extension aptly named, HTTPS Everywhere.
Unfortunately, malvertisers have already "abused" HTTPS to get unsuspecting users to download banking Trojans. Nonetheless, we are generally moving towards a safer, encrypted internet, and HTTPS protocols are an essential component to this trend.
Stay safe out there on the digital frontier and always practice safe browsing.