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Re: [keyassure] Interpreting certificates (and summary)

Peter Gutmann <pgut001@cs.auckland.ac.nz> Wed, 23 February 2011 08:07 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: mrex@sap.com
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Date: Wed, 23 Feb 2011 21:08:27 +1300
Cc: keyassure@ietf.org
Subject: Re: [keyassure] Interpreting certificates (and summary)
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Martin Rex <mrex@sap.com> writes:

>While in theory, it should be possible to ASN.1 re-encode -- I would be
>careful.  There are CAs out there with defective PKI-Software, distributing
>X.509 certs that are not valid ASN.1 DER.

You never, ever try to re-encode certs, because waaaay too many of them break
if you try it.  This has been standard practice for about 15-20 years now, the
rule of thumb is "there is only one (re-)encoding rule and its name is
memcpy()" (with a corollay of "there is only one X.500 name comparison rule
and it's name is memcmp()").

Peter.

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