SSL Certificate Articles
In-depth guides on SSL/TLS certificates — how they work, how to read them, common errors, and best practices.
Written for developers and sysadmins who deal with certificates day-to-day: deploying them, debugging errors, choosing the right type, and understanding what a CA actually does when it signs your CSR.
How to Read a Signature Algorithm in an SSL Certificate
The signature algorithm in an SSL certificate tells you how the CA signed it. Learn to read these fields and understand why algorithm choice matters for security.
Self-Signed Certificates: When to Use Them (and When Not To)
Self-signed certificates are free to generate and require no CA. Learn when they're appropriate and when they cause problems.
How to Check If Your SSL Certificate Is Properly Installed
After installing an SSL certificate, verify it's working correctly. Learn how to check with OpenSSL, browsers, and online tools — and what errors to look for.
The Role of Certificate Serial Numbers in PKI
Every SSL certificate has a unique serial number assigned by the issuing CA. Learn what serial numbers are, how they're used, and how to read them.
Certificate Revocation: CRL vs OCSP — Which Is Better?
CRL and OCSP are the two main mechanisms for revoking SSL certificates. Compare how they work, their tradeoffs, and which browsers actually rely on.
Understanding HSTS and How It Works with Your SSL Certificate
HSTS tells browsers to always use HTTPS for your domain. Learn how it works, how to enable it, and what happens when an HSTS certificate expires.
Extended Validation Certificates in 2026: Are They Still Worth It?
Browsers removed the green address bar for EV certificates in 2019. Do EV certs still offer meaningful security benefits? Here's the current state of EV.
How to Debug SSL Handshake Failures: A Practical Guide
SSL handshake failures can have many causes. This guide covers the most common errors, how to diagnose them with OpenSSL, and how to fix them.
Wildcard Certificates vs Multi-Domain SANs: Pros and Cons
Wildcard certificates cover all subdomains with one cert. SAN certificates list specific domains. Compare the tradeoffs to pick the right approach.
How to Generate a CSR: Step-by-Step for Any Web Server
A CSR is required to get an SSL certificate from a CA. Learn how to generate one with OpenSSL, Nginx, Apache, and IIS, and what fields to fill in.
What Is OCSP Stapling and How Does It Speed Up SSL?
OCSP stapling lets your server pre-fetch revocation status so browsers don't need to. Learn how it works and how to enable it on Nginx and Apache.
Understanding Key Usage and Extended Key Usage in SSL Certificates
Key Usage and Extended Key Usage extensions define what a certificate's key can be used for. Learn to read them and understand why they matter.
TLS 1.3 vs TLS 1.2: What Changed and Why It Matters
TLS 1.3 is faster and more secure than TLS 1.2. Learn what changed in the handshake, which cipher suites were removed, and how to check which version your server supports.
Let's Encrypt vs Paid SSL Certificates: Which Is Right for You?
Let's Encrypt provides free, automated DV certificates. Paid certificates offer OV and EV validation. Learn when to use each.
How to Renew Your SSL Certificate Without Downtime
Renewing an SSL certificate doesn't have to take your site offline. Learn the right sequence: generate a new CSR, get the new cert, install it, verify.