sec-label.xsd

<?xml version='1.0' encoding='UTF-8'?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="urn:xmpp:sec-label:0"
    xmlns="urn:xmpp:sec-label:0" elementFormDefault="qualified">

    <xs:annotation>
      <xs:documentation>
        The protocol documented by this schema is defined in
        XEP-0258: https://xmpp.org/extensions/xep-0258.html
      </xs:documentation>
    </xs:annotation>

    <xs:simpleType name="colorCSS">
        <xs:annotation>
            <xs:documentation>CSS colors (W3C colors + "orange")</xs:documentation>
        </xs:annotation>
        <xs:restriction base="xs:string">
            <xs:enumeration value="aqua"/>
            <xs:enumeration value="black"/>
            <xs:enumeration value="blue"/>
            <xs:enumeration value="fuschia"/>
            <xs:enumeration value="gray"/>
            <xs:enumeration value="green"/>
            <xs:enumeration value="lime"/>
            <xs:enumeration value="maroon"/>
            <xs:enumeration value="navy"/>
            <xs:enumeration value="olive"/>
            <xs:enumeration value="purple"/>
            <xs:enumeration value="red"/>
            <xs:enumeration value="silver"/>
            <xs:enumeration value="teal"/>
            <xs:enumeration value="white"/>
            <xs:enumeration value="yellow"/>
            <xs:enumeration value="orange"/>
        </xs:restriction>
    </xs:simpleType>

    <xs:simpleType name="colorRGB">
        <xs:annotation>
            <xs:documentation>Hex encoded RGB</xs:documentation>
        </xs:annotation>
        <xs:restriction base="xs:string">
            <xs:pattern value="#[0-9A-Fa-f]{6}"/>
        </xs:restriction>
    </xs:simpleType>

    <xs:simpleType name="color">
        <xs:annotation>
            <xs:documentation>Color</xs:documentation>
        </xs:annotation>
        <xs:union memberTypes="colorCSS colorRGB"/>
    </xs:simpleType>

    <xs:complexType name="displaymarking">
        <xs:annotation>
            <xs:documentation>Display Marking</xs:documentation>
            <xs:documentation>String to be prominently displayed along with labeled
                object.</xs:documentation>
        </xs:annotation>
        <xs:simpleContent>
            <xs:extension base="xs:string">
                <xs:attribute name="bgcolor" type="color" use="optional" default="white"/>
                <xs:attribute name="fgcolor" type="color" use="optional" default="black"/>
            </xs:extension>
        </xs:simpleContent>
    </xs:complexType>

    <xs:complexType name="label">
        <xs:choice minOccurs="0">
            <xs:any namespace="##other" processContents="lax"/>
        </xs:choice>
    </xs:complexType>

    <xs:element name="securitylabel">
        <xs:annotation>
            <xs:documentation>A Security Label</xs:documentation>
        </xs:annotation>
        <xs:complexType>
            <xs:sequence>
                <xs:element name="displaymarking" type="displaymarking">
                    <xs:annotation>
                        <xs:documentation>A Display Marking</xs:documentation>
                        <xs:documentation>To be prominently displayed</xs:documentation>
                    </xs:annotation>
                </xs:element>
                <xs:element name="label" type="label">
                    <xs:annotation>
                        <xs:documentation>The Primary Label</xs:documentation>
                    </xs:annotation>
                </xs:element>
                <xs:element name="equivalentlabel" type="label" minOccurs="0" maxOccurs="unbounded">
                    <xs:annotation>
                        <xs:documentation>An Equivalent Label</xs:documentation>
                    </xs:annotation>
                </xs:element>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
</xs:schema>