Let’s Encrypt is a CA. It differs from the rest in that they offer:
- Free domain-validated certificates;
- Free subdomain certificates (you’ll need to specify them during registration);
- Automated installation and renewal for many server configurations.
Their certicates expire in 3 months, but as mentioned, these can be renewed automatically if you have a supported configuration.
As per #2, you can specify what subdomains you want when you request a certificate. So why is their offering free wildcard certificates a big deal? For me, it’s because companies (especially blog providers like Tumblr, and technical service providers like hook.io) finally have a viable way of offering free
https subdomains and custom domain/subdomain names to their users.
Visit aidemo.hook.io. It will give you a scary warning, but if you click through, it will still give you an encrypted connection, but this time with something like Not secure in your browser. Once hook.io sets up a wildcard certificate, this warning won’t appear.
I am also looking forward to this as I have a personal project in mind that will definitely benefit from wildcard certs. Here’s to 2018!