X.509 Certificate Decoder
Paste a PEM, base64, or hex certificate to read its subject, issuer, validity window, public key, and v3 extensions, with SHA-256 and SHA-1 fingerprints. Runs entirely in your browser.
Certificates & PKIDecoding and fingerprints run locally. The certificate never leaves your browser.
References
- RFC 5280 - Internet X.509 PKI Certificate and CRL Profile
- ITU-T X.690 - ASN.1 encoding rules (BER, CER, DER)
- RFC 4514 - String Representation of Distinguished Names
- RFC 5480 - Elliptic Curve Cryptography Subject Public Key Info
- RFC 6960 - X.509 Internet PKI Online Certificate Status Protocol
- RFC 7633 - X.509 TLS Feature Extension (Must-Staple)