In Part 6 (1.05.03) 'https://reference.opcfoundation.org/Core/Part6/v105/docs/E.3' the 'SubjectName' in a 'CertificateIdentifier' is defined and described.

• It refers to RFC4514 'https://datatracker.ietf.org/doc/html/rfc4514#section-3'.
• The description of the 'X.500 AttributeType' refers to RFC4519 'https://datatracker.ietf.org/doc/html/rfc4519#section-2'.
• It is again described in Part 12 and Part 18, but different.

In Part 6 (1.05.03) 'https://reference.opcfoundation.org/Core/Part6/v105/docs/6.2.2' the 'subject', 'issuer' and 'subjectAltName' ist defined and described, but references RFC 5280 'https://datatracker.ietf.org/doc/html/rfc5280' and the 'Subject' description can be found in 'https://datatracker.ietf.org/doc/html/rfc5280#section-4.1.2.6' which refers to 'Issuer' -'https://datatracker.ietf.org/doc/html/rfc5280#section-4.1.2.4' and finally to RFC 4519 'https://datatracker.ietf.org/doc/html/rfc4519'.

In Part 12 (1.05.02) 'https://reference.opcfoundation.org/GDS/v105/docs/7.9.4' (StartNewKeyPairRequest) and 'https://reference.opcfoundation.org/GDS/v105/docs/7.10.7' (CreateSigningRequest​) the 'subjectName' is decribed different from Part 6 and Part 18.

• If the value contains a ‘/’ or a ‘=’ then it shall be enclosed in double quotes (‘”’).

In Part 18 (1.05.03) 'https://reference.opcfoundation.org/Core/Part18/v105/docs/4.4.3' it is described different than in Part 12 and Part 6.

• The name shall be one of entries in Table 8 and shall be followed by a '=' and then followed by the value, which is always enclosed in double quotes ('"').

Questions:

• Why it is defined in Part 12, Part 18 and twice in Part 6?
• Why during the virtual F2F-Meeting (06/12/24 - Afternoon meeting from minutes ~00:04:10 to ~00:13:45) the desicion was made, that if the 'subjectName' does not contain any '=' that it is not anymore allowed to be the CommonName?
  • But, this is clearly stated in Part 6 Values that do not contain '=' characters are presumed to be the Common Name component.
• Why in Part 12 the restriction is made to ‘CN’, ‘O’, ‘OU’, ‘DC’, ‘L’, ‘S’ or ‘C’ only - that severely restricts the definition in Part 6 (RFC4514/RFC4519)?
• The mentioned RFC4514 in Part 6 assumes, that the String 'X.500 AttributeType' should be written in capital letters (‘CN’, ‘O’, ‘OU’, ‘DC’, ...), but in RFC4519 where these attribute types are descriped they are written in lower case letters (‘cn’, ‘o’, ‘ou’, ‘dc’, ...).
  • Are both writings (UPPER and lower case) allowed considering both RFC4514 and RFC4519?

Recommentation:

• The SubjectName should be described ONLY ONCE in Part 6.
• The writing should identical 'SubjectName' and not 'subject' as in Part 12 or ' subject name' or 'name' as in Part 18 if it means the same.
• Revert the desicion made for the Common Name during the virtual F2F-Meeting.