SSL Certificate Decoder | decode SSL certificate into readable format

Certificate Decoder

About Certificate Decoder

SSL Certificate Decoder is a tool that allows you to decode an SSL certificate into readable format. It can be used to help diagnose problems with SSL certificates, or simply to understand how a particular certificate was created.

Codes for the different parts of the SSL Certificate are generated, including:

  • Version: 1.0 (not all versions are supported)
  • Subject: The subject name of the certificate
  • Issuer: The issuer name of the certificate
  • Public Key Algorithm: The public key algorithm used in the certificate
  • Validity: The validity period of the certificate, as well as it's effective and/or expiration dates
  • Serial Number: A serial number assigned to the certificate by its issuing CA. This number is usually unique and can be used to identify individual certificates issued by that CA.

Decoding a certificate is done by looking at the values in each field and comparing them to those of other known certificates. To decode an existing certificate, you must have access to the private key corresponding to that certificate. CAs generally do not provide such keys publicly and will provide them only under very specific circumstances (e.g., after a court order). Even if you have access to such a private key, it may not be feasible to decode a given certificate without knowing what algorithm was used to generate it. In this case, you should contact the issuing CA directly.