XEP-0434: Release version 0.3.0

Clarify usage, use real namespace for examples and add missing section:

* Clarify usage of trust messages by protocols such as Automatic Trust Management (ATM)
* Use namespace 'urn:xmpp:atm:0' of Automatic Trust Management (ATM) as example for 'usage' attribute.
* Add section 'Security Considerations'

xep-0434.xml

@@ -2,7 +2,7 @@
 <!DOCTYPE xep SYSTEM 'xep.dtd' [
 	<!ENTITY % ents SYSTEM 'xep.ent'>
 	<!ENTITY ns "urn:xmpp:trust-messages:0">
-	<!ENTITY ns-example-usage "urn:xmpp:example-usage:0">
+	<!ENTITY ns-atm "urn:xmpp:atm:0">
 	<!ENTITY ns-omemo "urn:xmpp:omemo:1">
 	<!ENTITY ns-sce "urn:xmpp:sce:0">
 %ents;
@@ -36,6 +36,19 @@
 		<email>melvo@olomono.de</email>
 		<jid>melvo@olomono.de</jid>
 		</author>
+	<revision>
+		<version>0.3.0</version>
+		<date>2020-12-19</date>
+		<initials>melvo</initials>
+		<remark>
+			<p>Clarify usage, use real namespace for examples and add missing section:</p>
+			<ul>
+				<li>Clarify usage of trust messages by protocols such as &xep0450;</li>
+				<li>Use namespace 'urn:xmpp:atm:0' of &xep0450; as example for 'usage' attribute.</li>
+				<li>Add section 'Security Considerations'</li>
+			</ul>
+		</remark>
+	</revision>
 	<revision>
 		<version>0.2.0</version>
 		<date>2020-11-05</date>
@@ -124,6 +137,7 @@
 <section1 topic='Why Trust Messages?' anchor='why-trust-messages'>
 	<p>
 		Trust messages can be used in conjunction with an end-to-end encryption protocol such as &xep0373; or &xep0384; to automatically or semi-automatically establish secure channels protected against active attacks.
+		This protocol specifies how trust messages are transmitted and protocols such as &xep0450; specify how and for which purpose they are processed.
 	</p>
 	<section2 topic='General Advantages' anchor='why-trust-messages-general-advantages'>
 		<p>
@@ -244,8 +258,8 @@
 	<p>
 		In the following example, two &xep0384; keys of Alice are indicated as trusted, one key of Bob is indicated as trusted and two other ones of Bob are indicated as untrusted.
 	</p>
-	<example caption='Trust Message Element for Alice&apos;s and Bob&apos;s OMEMO Keys'><![CDATA[
-<trust-message xmlns=']]>&ns;<![CDATA[' usage=']]>&ns-example-usage;<![CDATA[' encryption=']]>&ns-omemo;<![CDATA['>
+	<example caption='Trust Message Element for Alice&apos;s and Bob&apos;s OMEMO Keys used by ATM'><![CDATA[
+<trust-message xmlns=']]>&ns;<![CDATA[' usage=']]>&ns-atm;<![CDATA[' encryption=']]>&ns-omemo;<![CDATA['>
   <key-owner jid='alice@example.org'>
     <trust>6850019d7ed0feb6d3823072498ceb4f616c6025586f8f666dc6b9c81ef7e0a4</trust>
     <trust>221a4f8e228b72182b006e5ca527d3bddccf8d9e6feaf4ce96e1c451e8648020</trust>
@@ -310,7 +324,7 @@
   <from jid='alice@example.org/notebook'/>
   <to jid='carol@example.com'/>
   <payload>
-    <trust-message xmlns=']]>&ns;<![CDATA[' usage=']]>&ns-example-usage;<![CDATA[' encryption=']]>&ns-omemo;<![CDATA['>
+    <trust-message xmlns=']]>&ns;<![CDATA[' usage=']]>&ns-atm;<![CDATA[' encryption=']]>&ns-omemo;<![CDATA['>
       <key-owner jid='alice@example.org'>
         <trust>6850019d7ed0feb6d3823072498ceb4f616c6025586f8f666dc6b9c81ef7e0a4</trust>
         <trust>221a4f8e228b72182b006e5ca527d3bddccf8d9e6feaf4ce96e1c451e8648020</trust>
@@ -353,6 +367,12 @@
 		Keep in mind that a trust message SHOULD only be encrypted for endpoints with authenticated keys.
 	</p>
 </section1>
+<section1 topic='Security Considerations' anchor='security-considerations'>
+	<p>
+		Protocols using trust messages SHOULD specify rules for processing them in order to create or sustain a secure communication.
+		Therefore, those protocols SHOULD state in which cases from which senders trust messages are used for making trust decisions and for which keys they are sent to whom.
+	</p>
+</section1>
 <section1 topic='IANA Considerations' anchor='iana-considerations'>
 	<p>This document requires no interaction with the Internet Assigned Numbers Authority (IANA).</p>
 </section1>