Websites and online services use SSL (Secure Sockets Layer) certificates to encrypt data exchanged between a user’s web browser and the server.
Understanding how to read SSL certificates using OpenSSL in a Linux terminal can be a valuable skill for IT Professionals, system administrators, and anyone interested in enhancing their cybersecurity knowledge.
`Here’s a step-by-step guide on how to read SSL certificates using OpenSSL in a Linux terminal:
How to Check SSL Certificate in Linux
1. Check OpenSSL Installation:
Before you start, ensure that OpenSSL is installed on your Linux system. You can check its presence by running the following command:
# openssl version 2. View Certificate Information:
To view the complete details of an SSL certificate, including the subject, issuer, and validity dates, use the following command:
# openssl x509 -in certificate.crt -noout -text
Replace certificate.crt with the actual path to your certificate file.
3. Extract the Common Name (CN):
If you’re interested in the Common Name (CN) of the certificate (usually the domain name), you can use this command:
# openssl x509 -in certificate.crt -noout -subject 4. Verify Issuer Information:
To check the issuer’s information (the entity that issued the certificate), run:
# openssl x509 -in certificate.crt -noout -issuer 5. Confirm Certificate Expiration:
To ensure the certificate is still valid, check its expiration dates with:
# openssl x509 -in certificate.crt -noout -dates Understanding these basic commands will help you interpret SSL certificates effectively. Whether you’re a website owner verifying your own certificate or a security-conscious user confirming a website’s authenticity, the ability to read SSL certificates using OpenSSL in a Linux terminal is a valuable skill.
