<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Christian:<div class=""><br class=""></div><div class="">No, RFC 5280 does not obsolete RFC 3161. RFC 5280 obsoletes RFCs 3280, 4325, and 4630.<div class=""><br class=""></div><div class="">Anyway, RFC 5280 and RFC 3161 are consistent.</div><div class=""><br class=""></div><div class="">RFC 5280 says that the certificate issuer can make the EKU extension critical or non-critical.</div><div class=""><br class=""></div><div class="">RFC 3161 says that for use with the Time-Stamp Protocol, the certificate issuer MUST make the EKU extension critical, and it MUST contain id-kp-timeStamping.</div><div class=""><br class=""></div><div class="">Russ<br class=""><div class=""><br class=""></div><div class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Jan 28, 2022, at 9:56 AM, <a href="mailto:weber@infotech.de" class="">weber@infotech.de</a> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div class="">
Dear Russ,<br class="">
<br class="">
thanks for your reply.<br class="">
<br class="">
OK, i got it, but RFC 5280 obsoletes RFC 3161 and says:<br class="">
<br class="">
<pre class="newpage"><span class="h5"><a class="selflink" id="section-4.2.1.12" href="https://datatracker.ietf.org/doc/html/rfc5280#section-4.2.1.12">4.2.1.12</a>. Extended Key Usage</span>
This extension indicates one or more purposes for which the certified
public key may be used, in addition to or in place of the basic
purposes indicated in the key usage extension. In general, this
extension will appear only in end entity certificates. This
extension is defined as follows:
id-ce-extKeyUsage OBJECT IDENTIFIER ::= { id-ce 37 }
ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
KeyPurposeId ::= OBJECT IDENTIFIER
Key purposes may be defined by any organization with a need. Object
identifiers used to identify key purposes MUST be assigned in
accordance with IANA or ITU-T Recommendation X.660 [<a href="https://datatracker.ietf.org/doc/html/rfc5280#ref-X.660" title=" Information technology - Open Systems Interconnection - Procedures for the operation of OSI Registration Authorities: General procedures" class="">X.660</a>].
<u class=""> This extension MAY, at the option of the certificate issuer, be
either critical or non-critical.</u>
If the extension is present, then the certificate MUST only be used
for one of the purposes indicated. If multiple purposes are
indicated the application need not recognize all purposes indicated,
as long as the intended purpose is present. Certificate using
applications MAY require that the extended key usage extension be
present and that a particular purpose be indicated in order for the
certificate to be acceptable to that application.
So what?
BTW: The further obsoletions RFC i.e. Updated by: <a href="https://datatracker.ietf.org/doc/html/rfc6818" class="">6818</a>, <a href="https://datatracker.ietf.org/doc/html/rfc8398" class="">8398</a>, <a href="https://datatracker.ietf.org/doc/html/rfc8399" class="">8399</a>
do not affect RCF 5280 in this matter.
The main question remains: How to handle this issue?
Thanks In Advance
--
Christian Weber
</pre>
<div class="moz-cite-prefix">Am 28.01.2022 um 13:58 schrieb Russ
Housley:<br class="">
</div>
<blockquote type="cite" cite="mid:0832AA25-049C-4243-B9A1-FC75D6F6626C@vigilsec.com" class="">
<pre class="moz-quote-pre" wrap="">RFC 3161 says:
2.3. Identification of the TSA
The TSA MUST sign each time-stamp message with a key reserved
specifically for that purpose. A TSA MAY have distinct private keys,
e.g., to accommodate different policies, different algorithms,
different private key sizes or to increase the performance. The
corresponding certificate MUST contain only one instance of the
extended key usage field extension as defined in [RFC2459] Section
4.2.1.13 with KeyPurposeID having value:
id-kp-timeStamping. This extension MUST be critical.
The following object identifier identifies the KeyPurposeID having
value id-kp-timeStamping.
id-kp-timeStamping OBJECT IDENTIFIER ::= {iso(1)
identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7)
kp (3) timestamping (8)}
</pre>
<blockquote type="cite" class="">
<pre class="moz-quote-pre" wrap="">On Jan 28, 2022, at 6:25 AM, <a class="moz-txt-link-abbreviated" href="mailto:weber@infotech.de">weber@infotech.de</a> wrote:
Dear OpenSSL users,
recently we checked an older timestamp using the OpenSSL Library version 1.1.1i.
The check revealed, that the timestamp verification failed.
Digging into the code we found that if an eku entry for timestamping is preset
it is expected to be marked critical (see v3_purp.c:798 ff.).
Thats's not the case for the timetamp cert in use.
We couldn'f find any source that enforces the critical flag on eku timestamp entries.
RFC 5280 says, that makring the EKU as critical is deliberate tu the issuer.
Any thoughts or pointer to the mentioned requirement?
Thanks in advance
--
Christian Weber
</pre>
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<pre class="moz-quote-pre" wrap=""></pre>
</blockquote>
<br class="">
<pre class="moz-signature" cols="72">--
Christian Weber
Entwicklung - Verteilte Systeme
<a class="moz-txt-link-freetext" href="mailto:Weber@InfoTech.de">mailto:Weber@InfoTech.de</a>
--
Infotech Gesellschaft für
Informations- und Datentechnik mbH
Tel. +49-2361-9130-0
Fax +49-2361-9130-105
Geschäftsführer
Rainer Hans
Gerichtsstand Recklinghausen
Amtsgericht Recklinghausen HRB 1912
USt.-IdNr. DE-811565628</pre>
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