Secure SSL Cert Decoder – Online ssl decoder Tool
Decode and inspect SSL/TLS certificates (X.509).
Decode and Inspect SSL Certificates
Understanding the contents of an SSL/TLS certificate is crucial for debugging web server issues and verifying security. Our decoder parses X.509 PEM certificates and presents them in a human-readable format, allowing you to see the owner, the issuer, and the exact expiration date.
Key Certificate Fields Explained
- Subject: The entity (usually a website domain) that the certificate was issued to.
- Issuer: The Certificate Authority (CA) that verified the identity of the owner and signed the certificate.
- Validity Period: The specific time range during which the certificate is considered valid by web browsers.
- Fingerprint: A unique hash value that represents the entire certificate, used for easy verification.
100% Client-Side Processing
Safety is paramount when handling security assets. Our SSL Decoder runs entirely in your browser using node-forge. Your certificate data is never uploaded to any server, ensuring that your public keys and identification details remain private.
Frequently Asked Questions
X.509 is a standard format for public key certificates. It is the basis for SSL/TLS, which secures web traffic (HTTPS).
An SSL certificate contains the public key, the identity of the owner (Subject), the identity of the Certificate Authority that signed it (Issuer), and the validity period (Not Before/Not After).
Yes. Certificates contain public information. This tool processes the data entirely in your browser, so your certificate is never sent to a server.
Related Free Tools
- SSL CSR Generator — Generate Certificate Signing Requests (CSR) for SSL.
- Public Key Viewer — View details and fingerprints of RSA/SSH public keys.