SSL certificates contain important information about domain ownership, validity periods, certificate authorities, and security configurations. Our SSL Decoder tool parses and displays certificate details in a human-readable format, making it easy to understand certificate contents, validity, SAN (Subject Alternative Names), extensions, and thumbprints. Essential for security audits, certificate management, and troubleshooting SSL issues.
How it works
Paste a PEM-encoded certificate, upload a certificate file, or enter a domain name to fetch its certificate.
The tool parses the certificate structure, extracting all fields and extensions.
Certificate details are decoded and displayed, including subject, issuer, validity dates, public key information, and extensions.
SAN (Subject Alternative Names) are listed, showing all domains covered by the certificate.
Additional information like certificate chain, thumbprints, and signature algorithms are also displayed.
Why it matters
Verify certificate validity and expiration dates to prevent unexpected certificate expirations.
Audit certificate configurations to ensure they meet security and compliance requirements.
Debug SSL issues by examining certificate details and identifying configuration problems.
Understand certificate contents for security reviews and certificate management.
Check SAN coverage to ensure all your domains are properly covered by the certificate.
FAQ
What is a PEM certificate?
PEM (Privacy-Enhanced Mail) is a base64-encoded format for certificates. It's the most common format and starts with "-----BEGIN CERTIFICATE-----" and ends with "-----END CERTIFICATE-----".
What are Subject Alternative Names (SAN)?
SANs allow a single certificate to cover multiple domain names. For example, a certificate can cover example.com, www.example.com, and api.example.com all in one certificate.
How do I know if my certificate is valid?
Check the validity dates in the decoded certificate. The certificate must be within its "Not Before" and "Not After" dates, and the domain must match the certificate's subject or SAN entries.
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