Digital Certificate Viewer
Decode and analyze X.509 SSL/TLS certificates. View detailed certificate information, validity periods, extensions, and security details. All processing happens locally in your browser.
Paste a PEM-encoded certificate above to get started
Understanding Digital Certificates
What are Digital Certificates?
Digital certificates are electronic documents that use cryptographic signatures to bind public keys with identities. They are issued by Certificate Authorities (CAs) and serve as digital passports for secure communications.
X.509 is the standard format for public key certificates, widely used in TLS/SSL, email encryption, and code signing.
Certificate Components
- • Subject: Entity the certificate identifies
- • Issuer: Certificate Authority that signed it
- • Public Key: Cryptographic key for encryption
- • Validity Period: When certificate is valid
- • Extensions: Additional certificate properties
- • Signature: CA's digital signature
Certificate Use Cases
Web Security (SSL/TLS)
- • HTTPS website encryption
- • Server identity verification
- • Browser trust indicators
- • Protection against man-in-the-middle attacks
Code Signing
- • Software authenticity verification
- • Publisher identity confirmation
- • Malware protection
- • App store distribution
Email Security
- • S/MIME email encryption
- • Digital signatures
- • Sender authentication
- • Message integrity
Certificate Security Considerations
Certificate Validation
Always verify certificate validity, including expiration dates, issuer trust, and domain name matches. Check for proper certificate chain validation.
Key Management
Proper key size and algorithms are crucial. Modern certificates should use RSA 2048+ bits or ECC 256+ bits with SHA-256 or stronger hashing.
Certificate Renewal
Monitor certificate expiration dates and renew well before expiry. Expired certificates can cause service outages and security warnings.
Revocation Checking
Implement proper certificate revocation checking via CRL or OCSP to ensure certificates haven't been compromised or revoked.
How Our Viewer Works
Our Certificate Viewer uses the node-forge library to parse X.509 certificates directly in your browser. It supports standard PEM-encoded certificates and provides comprehensive analysis of certificate structure and contents.
Analysis Features
- • Complete certificate parsing
- • Validity period checking
- • Extension interpretation
- • Fingerprint calculation
- • Public key analysis
Security & Privacy
- • Client-side processing only
- • No server uploads
- • Complete data privacy
- • Offline capability
- • Open source libraries
The tool handles standard certificate formats and provides detailed breakdowns of all certificate components, making it ideal for security professionals, developers, and system administrators who need to examine certificate properties.