SSL Certificate Decoder
Inspect and decode PEM-encoded X.509 certificates, view validity periods, subject alternative names (SAN), and issuer details instantly.
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SSL / TLS Reference
1. X.509 Format & PEM
Certificates are encoded in Base64 DER format wrapped with header and footer boundary markers (`-----BEGIN CERTIFICATE-----`).
2. Subject Alternative Names (SAN)
Modern browsers require SAN extensions to validate multiple subdomains and domain variations under a single certificate.
How to use SSL Certificate Decoder
- Enter or paste the values requested in the input fields.
- Choose any options provided, then run an action button if the tool requires one.
- Review the result and copy or adjust it as needed.
SSL Certificate Decoder features
- Available tool controls: Decode Certificate.
- Input and option fields: Paste PEM Certificate Data (-----BEGIN CERTIFICATE-----):, Certificate Summary:, Parsed X.509 Attributes:.
Frequently Asked Questions (FAQ)
No. Public certificates contain only public keys and metadata. Never paste your private key (`-----BEGIN PRIVATE KEY-----`) into online decoders.
Root certificates are pre-installed in client operating systems and browsers, while intermediate certificates act as stepping stones issued by the root to sign end-entity server certificates.
Lookups and structure parsing execute locally in your browser to inspect attribute blocks and structural properties instantly.