Add ProtoXEP: GRE Encrypter: OpenPGP

This GRE Encrypter uses OpenPGP to encrypt payload.

inbox/gre-encrypter-openpgp.xml

@@ -0,0 +1,106 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!DOCTYPE xep SYSTEM 'xep.dtd' [
+  <!ENTITY % ents SYSTEM 'xep.ent'>
+%ents;
+]>
+<?xml-stylesheet type='text/xsl' href='xep.xsl'?>
+<xep>
+<header>
+  <title>GRE Encrypter: OpenPGP</title>
+  <abstract>This GRE Encrypter uses OpenPGP to encrypt payload.</abstract>
+
+  &LEGALNOTICE;
+  <number>xxxx</number>
+  <status>ProtoXEP</status>
+  <type>Standards Track</type>
+  <sig>Standards</sig>
+  <approver>Council</approver>
+  <dependencies>
+    <spec>XMPP Core</spec>
+    <spec>XEP-0001</spec>
+    <spec>XEP-0373</spec>
+  </dependencies>
+  <supersedes/>
+  <supersededby/>
+  <shortname>gre-encrypter-openpgp</shortname>
+  <tags>
+    <tag>gre</tag>
+    <tag>encrypter</tag>
+  </tags>
+  <author>
+    <firstname>Jérôme</firstname>
+    <surname>Poisson</surname>
+    <email>[email protected]</email>
+    <jid>[email protected]</jid>
+  </author>
+  <revision>
+    <version>0.0.1</version>
+    <date>2025-01-12</date>
+    <initials>jp</initials>
+    <remark><p>First draft.</p></remark>
+  </revision>
+</header>
+
+<section1 topic='Introduction' anchor='intro'>
+  <p>This XEP defines a GRE Encrypter that uses OpenPGP. It is based on &xep0373; and uses the mechanisms defined there to handle keys.</p>
+</section1>
+
+<section1 topic="Requirements" anchor="reqs">
+  <p>The design goals of this GRE Encrypter are:</p>
+  <ul>
+    <li>Compliance with OpenPGP.</li>
+    <li>Re-use existing mechanisms of &xep0373;.</li>
+  </ul>
+</section1>
+
+<section1 topic="Encryption Process" anchor='encryption-process'>
+  <p>The encryption process using OpenPGP involves the following steps:</p>
+  <ol>
+    <li><strong>Data Preparation</strong>: The client prepares the data to be encrypted according to the specified formatter.</li>
+    <li><strong>Key Exchange</strong>: The client retrieves or generates the necessary public key(s) from the gateway as specified in &xep0373;.</li>
+    <li><strong>Encryption</strong>: The payload is encrypted using OpenPGP's public key(s) of recipient(s).</li>
+    <li><strong>Payload Construction</strong>: The encrypted data is encoded using base64 then wrapped in the &lt;encrypted/&gt; element as described in XEP-0XXX: Gateway Relayed Encryption, with appropriate attributes for formatter and encrypter namespaces.</li>
+  </ol>
+</section1>
+
+<section1 topic="Discovering Support" anchor="disco">
+  <p>If an entity supports the MIME GRE Formatter, it MUST advertise it by including the "urn:xmpp:gre:encrypter:openpgp:0" discovery feature in response to a &xep0030; information request.</p>
+  <example caption="Service Discovery Information Request"><![CDATA[
+<iq type='get'
+    from='[email protected]/balcony'
+    to='some_gateway.example.org'
+    id='disco1'>
+  <query xmlns='http://jabber.org/protocol/disco#info'/>
+</iq>]]></example>
+  <example caption="Service Discovery Information Response"><![CDATA[
+<iq type='result'
+    from='some_gateway.example.org'
+    to='[email protected]/balcony'
+    id='disco1'>
+  <query xmlns='http://jabber.org/protocol/disco#info'>
+    ...
+    <feature var='urn:xmpp:gre:0'/>
+    <feature var='urn:xmpp:gre:encrypter:openpgp:0'/>
+    ...
+  </query>
+</iq>]]></example>
+
+</section1>
+
+<section1 topic="Security Considerations" anchor="security">
+  <p>The security consideration of &xep0373; apply.</p>
+</section1>
+
+<section1 topic="IANA Considerations" anchor="iana">
+  <p>This document does not require interaction with &IANA;.</p>
+</section1>
+
+<section1 topic='XMPP Registrar Considerations' anchor='registrar'>
+  <p>TODO</p>
+</section1>
+
+<section1 topic="Acknowledgements" anchor="acks">
+  <p>Thanks to NLNet foundation/NGI Zero Core for funding the work on this specification.</p>
+</section1>
+
+</xep>