Secure Sockets Layer (SSL) is a cryptographic protocol that ensures secure communication over computer networks by preventing eavesdropping, as indicated by URLs starting with "https://" instead of "http://". SSL encrypts web communication to protect it from hackers, although its implementation can be challenging, which is why not all websites use it. Websites can activate SSL through their site host or system administrator, as it requires server-side activation. Let’s Encrypt aims to simplify the process of setting up, configuring, and renewing SSL certificates by offering free SSL certificates, potentially transforming the field.