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Re: X.509 v3 Certificate

1994-12-20 09:08:00
Steve:

One immediate observation about the proposed CRL format:

CertificateList ::= SIGNED { SEQUENCE {
    version             Version  OPTIONAL,
                        -- if present, version must be v2--
    signature           AlgorithmIdentifier, 
    issuer              Name,
    thisUpdate               UTCTime,
    nextUpdate               UTCTime OPTIONAL, 
    revokedCertificates      SEQUENCE OF SEQUENCE {
         userCertificate          CertificateSerialNumber, 
         revocationDate           UTCTime,
         crlEntryExtensions       Extensions OPTIONAL } OPTIONAL,
    crlExtensions       [0]  Extensions OPTIONAL }}
    
The OPTIONAL nature of the nextUpdate field is not consistent with
the CRL format in PEM RFC 1422.  Can you explain the reasoning ?

For some environments, nextUpdate was considered unnecessary, e.g., if the CRL 
issue cycle is fixed by policy and known to all users in an environment the 
field is not needed.  Nevertheless, for other environments, it is quite 
reasonable to say that this field must always be present (this amounts to 
"profiling" the standard).  The PEM (RFC 1422) environment is in the latter 
category, i.e., use of this field is mandated.  Assuming PEM starts using the 
new extension fields, other similar stipulations may arise.  For example, the 
PEM infrastructure spec. may mandate use of the RFC822Name field in all 
certificates for PEM use, even though this is an optional field in the 
standard.  
I do not see such differences as being incompatibilities - they simply reflect 
the situation that PEM use of X.509 represents a specialization of the more 
general standard.

Warwick

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