Knowing how to view certificates is an essential skill in the modern digital landscape, whether you are troubleshooting a website connection, verifying software authenticity, or managing your own security infrastructure. A digital certificate acts as a passport, verifying the identity of a person, device, or service and establishing a secure channel for communication. This guide walks you through the process step-by-step, covering the most common platforms and use cases without unnecessary technical jargon.
At the core of this process is the certificate file itself, which usually comes in formats like .CRT, .CER, or .P7B. These files contain the public key, identity information, and the digital signature of the issuing authority. Before you can inspect the contents, you must first locate the certificate, which might be stored in a web server, an email client, a physical file on your computer, or within the secure storage of your operating system.
Viewing Certificates in Web Browsers
The most frequent interaction users have with certificates occurs when browsing the web. When you see a padlock icon in the address bar, it indicates that the site is using a TLS certificate to secure the connection. To view the certificate details, you simply click the padlock icon. This action opens a side panel that provides information about the connection security and the site’s identity.
For a deeper inspection, most browsers allow you to navigate into the certificate chain. Clicking on the "Certificate" or "Connection is secure" option will open a new window displaying the certificate viewer. Here, you can examine the Issuer, the Valid date range, and the Subject Name. This view is invaluable for verifying that you are connecting to the genuine website and not a malicious imposter.
Inspecting Certificates on Windows
Using the Certificate Manager
Windows provides a robust built-in tool for managing certificates through the Certificate Manager (certmgr.msc). This console organizes certificates into categories such as "Trusted Root Certification Authorities" and "Personal." To open it, press the Windows key, type "certmgr," and hit enter. This interface is primarily used by administrators to import, export, or revoke digital identities.
To view a specific certificate, expand the folder category, double-click the certificate, and the Properties window will appear. The "Details" tab is particularly useful, as it displays the raw data in a readable format. You can see the Public Key, Thumbprint, and Enhanced Key Usage, which details exactly what the certificate is allowed to do, such as code signing or email encryption.
Viewing Certificates on macOS
Apple users rely on the Keychain Access application to manage their certificates. Located in the Utilities folder within Applications, Keychain Access provides a clean interface to view the certificates stored in your login keychain or the system keychain. Double-clicking a certificate expands a detailed view where you can see the actual data fields.
One of the most useful features here is the ability to verify the certificate’s validity chain. If a certificate is valid, the system will display a "Trust" section where you can set how macOS should handle the certificate. For viewing purposes, you can select the certificate and press the space bar to open a quick summary that shows the Issuer, subject, and expiration status at a glance.
Viewing Certificates on Linux
Linux offers powerful command-line tools for the tech-savvy user who prefers terminal interaction. The OpenSSL toolkit is the standard for this purpose, allowing you to view the contents of a certificate file without needing a graphical interface. By running a simple command, you can decode the certificate and read every line of its configuration.
