Re: Object identifiers and ASN.1 syntax

[Richard Levitte - VMS Whacker]

From: Rich Salz <[EMAIL PROTECTED]>
Subject: Re: Object identifiers and ASN.1 syntax
Date: Tue, 03 Oct 2000 14:43:05 -0400
Message-ID: <[EMAIL PROTECTED]>

rsalz> > One can see definitions like this:
rsalz> > 
rsalz> >         { iso standard 8571 abstract-syntax (2) }
rsalz> 
rsalz> The names aren't flat. To find out the number for "standard", you
rsalz> ask iso.  To find out the number of abstract-syntax, you ask the entity
rsalz> that maintains "8571" (you might have to ask "standard" who that is).

I'm not sure I grasp this completely.  Does that mean that if it
starts with a series of plain words, I simply see that part as an
array of words that kind of describe the path to follow to find out
the OID?  In this case, I would therefore parse "iso" and "standard",
get the list ("iso", "standard") and see that as a wordy thingy
describing '{ 1 0 }', and the rest has to be numbers?  Does that mean
that something like this would be precluded?

        { iso standard 8571 abstract-syntax }

What I'm trying to figure out is how I will best get together all the
information from reading a number of ASN.1 modules.  I'm wondering for
example how "standard" is defined.  Is it something like this?

        standard OBJECT IDENTIFIER ::= { iso 0 }

Or is it:

        standard OBJECT IDENTIFIER ::= { 0 }

(then, I gotta find all those modules, especially those defining the
basic OIDs.  And no, I don't have access do X.5nn)

rsalz> I'm not used to seeing a space before the "(2)" but I I suppose
rsalz> it's possible and/or legal. :)

That example was straight from ASN.1 Complete.  I really hope the
author knows what he's writing about :-).

rsalz> >         { id-pkix-ocsp 1 }
rsalz> > 
rsalz> > where 'id-pkix-ocsp' is the OID of the OCSP arc.
rsalz> 
rsalz> Yup, that's definitely in ASN.1

OK, that part is clear...

rsalz> >         id-stupid-OCSP-doubling OBJECT IDENTIFIER ::= {
rsalz> >                 id-pkix-ocsp id-pkix-ocsp 999 }
rsalz> 
rsalz> I don't see why you couldn't do that.  But I wouldn't bother to make
rsalz> *my* parser do anything other than gripe "got array wanted scalar" :)

Basically, grap and translate the names I get to OIDs, concatenate and
be happy with the result...

Also, I don't think that answered my question on what the result would
actually be...

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