[ig/security] Update Participation

 - Participation in discussions via mailing lists and GitHub is free, 
 - Participation in reviews, deliverable development, and meetings requires joining the group. The group also welcomes and encourages participants who have specific expertise and do not represent a W3C Member. In case they are invited experts but without member access.

2024/ig-security.html

@@ -228,15 +228,11 @@ <h3 id="external-coordination">External Organizations</h3>
         <h2 id="participation">
           Participation
         </h2>
-        <p>Participation in SING is open to the public. Participants who do not represent a W3C Member should join as <a href="https://www.w3.org/invited-experts/">Invited Experts</a>. Invited Experts in this group are not granted access to Member-only information.</p>
-        <p>
-          The group encourages questions, comments and issues on its public mailing lists and document repositories, as described in <a href='#communication'>Communication</a>.
-        </p>
-        <p>
-          The group also welcomes non-Members to contribute technical submissions for consideration upon their agreement to the terms of the <a href="https://www.w3.org/policies/patent-policy/">W3C Patent Policy</a>.
-        </p>
-        <p>Participants in the group are required (by the <a href="https://www.w3.org/policies/process/#ParticipationCriteria">W3C Process</a>) to follow the
-          W3C <a href="https://www.w3.org/policies/code-of-conduct/">Code of Conduct</a>.</p>
+        <p>To be successful, this Interest Group is expected to include Security Researchers, Threat Modeling experts, Cryptographers, Cryptoanalysts, and active Editors for each deliverable. The Chairs and Editors are expected to contribute half of a working day per week. There is no minimum requirement for other Participants.</p>
+	<p>Participation in discussions via mailing lists and GitHub is free, as described in <a href="#communication">Communication</a>.</p>
+	<p>Participation in reviews, deliverable development, and meetings requires joining the group. The group welcomes and encourages all participants with proven specific expertise, even if they do not represent a W3C Member. In that case, they should join as <a href="https://www.w3.org/invited-experts/">Invited Experts</a>. Invited Experts in this group are not granted access to Member-only information.</p>
+	<p>The group also welcomes non-Members to contribute technical submissions for consideration upon their agreement to the terms of the <a href="https://www.w3.org/policies/patent-policy/">W3C Patent Policy</a>.</p>
+        <p>Participants in the group are required (by the <a href="https://www.w3.org/policies/process/#ParticipationCriteria">W3C Process</a>) to follow the W3C <a href="https://www.w3.org/policies/code-of-conduct/">Code of Conduct</a>.</p>
       </section>
       <section id="communication">
         <h2>