sarwarfx // cert
X.509 Cryptographic Certificate Inspector

SSL CERTIFICATE // PEM INSPECTOR

Decode and verify X.509 PEM certificates client-side. Inspect Subject Alternative Names (SANs), expiration dates, and SHA-256 fingerprints.

PRIMARY COMMON NAME (CN)
--
ISSUING AUTHORITY (O / CN)
--
PUBLIC KEY & SIGNATURE
--
SUBJECT ALTERNATIVE NAMES (SANs)
--
SERIAL NUMBER (HEX)
--
SHA-256 FINGERPRINT
--
SHA-1 FINGERPRINT
--

X.509 PUBLIC KEY INFRASTRUCTURE (PKI) ARCHITECTURE

X.509 certificates form the cryptographic foundation of Transport Layer Security (TLS/HTTPS). Encoded in ASN.1 DER and serialized to ASCII PEM containers, they bind cryptographic public keys to authorized domain identities:

Subject Alternative Names (SANs) Modern browser trust stores mandate SAN entries for hostname verification, deprecating the legacy reliance on single Common Name (CN) attributes.
Validity Envelopes Strictly bounded between `notBefore` and `notAfter` timestamps. Browsers reject any certificate accessed outside this temporal window.
Zero-Trust Inspection Unlike external SSL checker endpoints that make unauthenticated outbound network scans, this tool parses your raw PEM certificate locally in your browser memory.