Certificate Decoder
Parse PEM or DER x509 SSL/TLS certificates to extract issuer, subject, Subject Alternative Names (SANs), validity dates, key algorithm, and SHA-256 fingerprint. Essential for certificate analysis and SSL/TLS auditing.
x509 Certificate Analysis for Security Testing
SSL/TLS certificates are a core part of web security. Decoding certificates allows you to verify certificate chains, identify misconfigurations, detect expired or self-signed certificates, and understand what domains are covered by a particular certificate. This tool supports both PEM (Base64-encoded with headers) and DER (binary) certificate formats.
Key Fields
- Subject: The entity the certificate was issued to (CN, O, L, ST, C)
- Issuer: The Certificate Authority that signed this certificate
- SAN: Subject Alternative Names — all domains this cert covers
- Fingerprint SHA-256: Unique hash to identify the certificate