Re: [pkix] DER encoding in RFC 3161

Peter Gutmann <pgut001@cs.auckland.ac.nz> Thu, 30 July 2020 10:15 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Phillip Hallam-Baker <phill@hallambaker.com>, Koichi Sugimoto <koichi.sugimoto=40globalsign.com@dmarc.ietf.org>
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Thread-Topic: [pkix] DER encoding in RFC 3161
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Date: Thu, 30 Jul 2020 10:15:40 +0000
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Subject: Re: [pkix] DER encoding in RFC 3161
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Phillip Hallam-Baker <phill@hallambaker.com> writes:

>It is sufficiently possible that there are ASN.1 parsers there that insist on
>strict DER with definite length encoding throughout

Highly unlikely, since too many things would break if you did this, the last
parser I know of that did this was in the mid-1990s.  The rule has always been
"take whatever blob the other side sends you and use that", thus my long ago
comment that "there is only one encoding rule and that is memcpy()".  So in
practice you don't need to worry about it.  I mean, in theory you should, but
in practice you don't.

Peter.