Cert Decoder is a free, user-friendly online tool for decoding X.509 SSL/TLS certificates in PEM format. It quickly extracts key certificate details, including the issuer, validity period, Subject Alternative Names (SAN), serial number, and fingerprint. All processing is done securely within your browser, ensuring no data is sent to external servers.
Key Features:
Certificate Details: Easily check information such as expiration dates and domain associations.
PEM Format Compatibility: Decode certificates encoded in base64 blocks that begin with "-----BEGIN CERTIFICATE-----" and end with "-----END CERTIFICATE-----".
Local Decoding: All operations are performed locally in your browser for maximum security.
About X.509 Certificates:
X.509 is an internationally recognized standard established by the International Telecommunication Union (ITU) that defines the structure of public key certificates. These certificates are fundamental to secure internet communication, particularly in protocols like TLS (Transport Layer Security) and SSL (Secure Sockets Layer), which enable HTTPS connections.
An X.509 certificate links an entity's identity—such as a domain name, organization, or individual—to a public key using a digital signature. This ensures the authenticity of the public key during secure communications. Certificates may be issued by trusted Certificate Authorities (CAs) or self-signed for internal or testing purposes.
Additional Information:
X.509 certificates are validated through a hierarchical trust model known as a certificate chain. Each certificate in the chain is authenticated by tracing back to a trusted root CA certificate. Proper management, renewal, and revocation of these certificates are essential for maintaining secure digital environments.
Cert Decoder streamlines the process of decoding and verifying SSL/TLS certificates, making it an indispensable tool for professionals managing secure communications.
Comments and Reviews
Great, simple tool to validate certificate details!