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C, O and CN fields are standard requirements to all certificates.
For sign certificate serialNumber is required for storing all the must have information. Server code is included to make each sign certificate unique (CA’s requirement) and to define the server that uses the certificate.
For auth certificate, serialNumber is there to make it easy to see to which the server that the certificate belongs. The is associated with. However, X-Road does not use any of the information stored in the auth certificate.
Java classes that implement the profile:
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