How to Use the Chrome DevTools Security Tab to View SSL Certificates

When you visit a website via HTTPS, a padlock icon appears in your browser’s address bar, indicating that the connection is encrypted. However, not all encryption is created equal. A website might be using an outdated TLS protocol, a weak cipher suite, or an SSL certificate issued by an untrusted authority. If you are a web developer debugging a \”Not Secure\” warning, or a security researcher auditing a site’s cryptographic hygiene, simply clicking the padlock icon does not provide enough raw data. For deep cryptographic inspection, you must use the Google Chrome DevTools \”Security\” tab.

Why Use the DevTools Security Tab?

The standard browser padlock menu provides a highly simplified, consumer-friendly overview of connection security. The DevTools Security tab, conversely, exposes the underlying mathematical handshake. It reveals the exact protocol version (e.g., TLS 1.2 vs TLS 1.3), the key exchange mechanism (e.g., X25519), and the specific cipher used to encrypt the traffic (e.g., AES_128_GCM). Furthermore, it allows you to view the full cryptographic chain of trust, verifying exactly which Certificate Authority (CA) signed the website’s public key.

Step 1: Open the Security Tab

The Security tab is a primary panel within the DevTools interface.

1. Open Google Chrome and navigate to the website you want to audit.
2. Right-click anywhere on the page and select Inspect.
3. Look at the top menu bar of the DevTools window (where Elements, Console, and Sources are located).
4. If you do not see the Security tab, click the >> icon (More tabs) and select it from the dropdown list.

Step 2: Analyze the Main Origin Connection

The Security Overview page provides an immediate diagnosis of the main HTML document’s connection.

1. Under the \”Security overview\” section, look for the Main origin header.
2. Below it, Chrome will output a plain-text summary of the cryptographic handshake. For example, it might state: \”The connection to this site is encrypted and authenticated using TLS 1.3, X25519, and AES_128_GCM.\”
3. If the connection is using an obsolete protocol (like TLS 1.0 or 1.1), this text will be flagged in red, indicating a severe vulnerability.

Step 3: Inspect the SSL Certificate

To ensure a website is not being impersonated, you must verify its digital identity.

1. On the Security tab, click the View certificate button located under the Main origin summary.
2. A native operating system dialog box will appear.
3. Click the Details tab. Here you can inspect the raw cryptographic data, including the Public Key size (e.g., RSA 2048 Bits), the Signature Algorithm (e.g., SHA-256), and the exact expiration date.
4. Click the Certification Path tab to view the hierarchical chain of trust, tracing the certificate from the website domain up to the Root Certificate Authority.

Step 4: Audit Mixed Content Errors

A website loaded over HTTPS will still be marked \”Not Secure\” if it pulls in images or scripts over unencrypted HTTP. This is known as Mixed Content.

1. If the site suffers from Mixed Content, the Security tab overview will display a prominent warning.
2. To locate the specific files causing the breach, look at the left sidebar of the Security tab and click on the specific origin domain flagged in red.
3. Chrome will list the exact network requests that were transmitted insecurely, allowing you to quickly rewrite those URLs in your source code.

By utilizing the DevTools Security tab, developers and analysts can move beyond the simplified padlock icon and mathematically verify the cryptographic integrity of any web server.