TLS Certificate
The security certificate that enables HTTPS
What is a TLS Certificate?
A TLS (Transport Layer Security) certificate is a digital certificate that enables encrypted HTTPS connections between your browser and a website. It contains information about the domain(s) it covers, who issued it, and when it expires.
We check whether the certificate is valid, hasn't expired, and actually matches the domain you're checking. We also look at the Subject Alternative Names (SANs) to see what other domains the certificate covers.
Why Do TLS Certificates Matter?
TLS certificates serve two main purposes:
- Encryption: They encrypt data transmitted between your browser and the website, protecting it from interception
- Identity: They help verify that you're connecting to the intended website, not an imposter
However, having a valid TLS certificate doesn't make a website trustworthy. Free certificates are easily obtained by anyone. It simply means the connection is encrypted.
How to Interpret This Signal
Valid certificate that matches the domain
Certificate expires soon or doesn't match domain
Certificate expired, invalid, or no HTTPS