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SSL/TLS Certificate Decoder – Analyze X.509 Certificates

Decode PEM/DER certificates, inspect subject/issuer, validity, and security details for TLS, email, or code signing assets.

🟢 Runs locally · no uploads

Certificate Decoder

Decode and analyze X.509 certificates

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SSL/TLS Certificates

Decode HTTPS website SSL/TLS certificates

verified
Code Signing

Decode code signing certificates for applications

mail
Email Certificates

Decode S/MIME certificates for encrypted email

account_tree
Root CA Certificates

Decode root certificate authority certificates

Certificate Input
Certificate Analysis
description

Certificate analysis will appear here

Characters: 0Lines: 1Size: 0 B

scienceExample Certificates

securityPEM Certificate
-----BEGIN CERTIFICATE-----
MIICzDCCAbQCCQCVEk4xJF7StjANBgkqhkiG9w0BAQsFADAoMQsw...
securitySimple URL
https://www.google.com...

keyboardKeyboard Shortcuts

keyboardShow shortcutsexpand_more
Ctrl+EnterDecode certificate
Ctrl+LClear all

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› About this tool · FAQ

Decode and analyze SSL/TLS X.509 certificates. Extract detailed information including subject, issuer, validity, public key, extensions, and perform security analysis.

What certificate formats are supported?

The tool supports PEM, DER, Base64 encoded certificates, and can fetch certificates directly from HTTPS URLs. Auto-detection helps identify the format automatically.

Can I analyze certificate chains?

The tool can analyze individual certificates and provide information about certificate chains when available. For complete chain validation, the full chain must be provided.

What security issues does the tool detect?

The tool checks for weak encryption algorithms, small key sizes, expired certificates, deprecated hash functions (SHA1, MD5), and compliance with modern security standards.

Is certificate data sent to servers?

No! All certificate parsing and analysis happens locally in your browser. Certificate data never leaves your device, ensuring complete privacy and security.

Can I analyze certificates from websites?

Yes! Enter an HTTPS URL and the tool will fetch and analyze the website's SSL certificate. This is useful for quick security checks and monitoring.