An X509 certificate is a common type of digital certificate used by most organizations. All certificates of this type will have basic information, which is defined by the standard for this certificate type. In addition to the common information, organizations have the ability to include optional details, which may or may not be present. Common data includes the encrypted public key, serial number, valid dates, version number, issuer, and other unique identifiers.
A Digital Signature in an X509 Certificate Can Be Generic or for an Individual
An X509 certificate will often contain a digital signature. The type of digital signature will depend upon how the certificate is being deployed. For instance, when it is being used to digitally sign electronic documents, the signature will be user specific. In cases, where it is being used by the organization, the digital signature could be that of the organization itself, rather than an individual.