🚀 go-pugleaf

Mark W. Eichin <eichin@athena.mit.edu> writes:
|
|	   This paper is "A Layman's Guide to a Subset of ASN.1, BER, and
|   DER" by Burton S. Kaliski Jr. of RSA DSI; it is written with an
|   emphasis on parts of ASN.1 needed to implement the PKCS standards.  It
|   refers to CCITT X.208 and X.209, not to the ISO documents -- perhaps
|   the above mentioned FAQ should explain the meaning of the distinction
|   between CCITT and ISO. (Erik Naggum's description of the two groups
|   was clear, but it didn't explain why the CCITT makes recommendations
|   in the first place, or which direction the standards flow...)

OK, I'll give it a shot.  CCITT made this OSI concept, not ISO.  ISO has
a track record of adopting useful standards wherever they are found, but
mistakenly thought CCITT's involvement in telematic services and higher
level stuff was useful, probably in the belief that the world's best
experts in wires, transmission, and other low-level communications stuff
also knew what people put their expertise to use for.  CCITT recommend-
ations are just that -- recommendations -- which the members of ITU, the
International Telecommunications Union, which are mostly government-run
monopoly telephone companies and the occasional Recognized Private
Operating Agencies (RPOA), known to CCITT as "Administrations",
generally adopt as their working procedures.  CCITT also cater to all
kinds of policy required to allow ITU members to use each other's
networks for transit, and has hairy protocols (the people-to-people
type) to set prices and thus allow international minimal connectivity.
The Internet could learn something from this, and I believe the IETF has
contacted CCITT to maybe let them handle the clearing processes involved
in a commercial Internet.

X.208 and X.209 are identical to ISO 8824 and ISO 8825, as amended.
You can get the X.200 series recommendations for about the price of the
cover page of ISO 8824 (well, not really, but substantially cheaper),
and ISO and CCITT work very hard to have their respective standards and
recommendations "technically aligned".  Had I known this a before I
bought ISO 8613 for several hundred dollers, I could have acquired T.400
for about one fourth of the cost.  Look closely before you buy.

|   Thanks for your patience. I suspect these questions are coming up
|   more often (from American developers, at least) due to the growing
|   use of SNMP, RSA PEM, and Kerberos version 5, specifications for
|   which are freely available yet which rest on ASN.1 in particular
|   which is not.

Hmmm.  ASN.1 has received much input from some RFC, and so has this
entire X.400 mess, let's see...  (grep'ing in the background :-)

841   National Bureau of Standards; NBS  Specification for message format for
      Computer Based Message Systems.  1983 January 27; 110 p. (Format:
      TXT=238774 bytes)  (Obsoletes RFC 806)

RFC 841 contains a rudimentary ASN.1 specification, due to the fact that
ASN.1 grew up in the message-handling world, or X.400 series, but was
found to be useful as a general mechanism and now lives in the X.200
series.

ASN.1 is really a quite simple and neat specification, once you get
through the language barrier that all ISO standards and CCITT
recommendations suffer from, but the BER is evil, both in specification
and in practice.  CCITT is said to suffer to "bitophobia" (abnormal fear
of wasted bits), and rather thinks that by the time anyone actually
implements ASN.1 BER, the computers won't notice the overhead in
unwinding the BER integer and floating-point formats.  (Sorry, this is
getting out of hand.)

I'll probably regret sending this.

Best regards,
</Erik>
--
Erik Naggum             |  ISO  8879 SGML     |      +47 295 0313
                        |  ISO 10744 HyTime   |
<erik@naggum.no>        |  ISO 10646 UCS      |      Memento, terrigena.
<enag@ifi.uio.no>       |  ISO  9899 C        |      Memento, vita brevis.