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Crypto ยท Certificate inspection

Decode any X.509 certificate

Paste PEM or base64-encoded DER and inspect every field - subject, issuer, validity, SANs, key info, extensions, and fingerprints. All parsing happens in this tab.

Runs locallyNo uploadpkijs

Certificate

Decoded fields

Paste a PEM block or base64-encoded DER and click Decode.

ASN.1 parsing via asn1js + pkijs. The certificate bytes never leave this tab. SHA-1 fingerprints are shown for legacy parity only - prefer SHA-256.