<page xmlns="http://projectmallard.org/1.0/"
      xmlns:its="http://www.w3.org/2005/11/its"
      type="guide" style="task"
      id="pgp-subkeys">
  <info>
    <link type="guide" xref="index#pgp-keys" group="second"/>

    <revision version="0.1" date="2011-10-23" status="stub"/>
    <revision pkgversion="3.9" version="0.1" date="2013-06-28" status="review"/>

    <include href="legal.xml" xmlns="http://www.w3.org/2001/XInclude"/>

    <credit type="author copyright">
      <name>Aruna Sankaranarayanan</name>
      <email its:translate="no">[email protected]</email>
      <years>2013</years>
    </credit>

    <desc>A subkey is always bound to a master key in a PGP keypair. It is
    used for encryption.</desc>
  </info>

  <title>What is a subkey?</title>

  <p>Though it is very important to keep your keys safe, it can become quite
  tedious to do so when you have many keys. <app>Passwords and Keys</app>
  provides a simple solution to key safety by using <em>subkeys</em> for
  signing and encryption.</p>

  <p>Whenever you <link xref="pgp-create">create</link> a new public encryption
  key, a <em>keypair</em> is generated instead of a single key. This keypair
  consists of a main key, also called the <em>master key</em> and a
  <em>subkey</em>. A master key can be used to create additional subkeys that
  are then bound to it.</p>

  <list>
    <title>What does each key in a keypair do?</title>
      <item>
	<p>The <em>master key</em> is used for
	<link xref="pgp-sign">signing</link> other keys, creating subkeys
	and <link xref="subkeys-revoke">revoking</link> subkeys. Your master key
	must be kept very safe. Signatures of trust are also collected on your
	master key. If the master key is compromised, you have no choice but to
	revoke it and all the subkeys attached to it.</p>
      </item>
      <item>
	<p>The default <em>subkey</em> is used for encryption and decryption
	of messages. Additional subkeys can be created for signing. Though it
	is important that your subkeys are kept safe, you can always revoke a
	subkey if it is compromised and create a new one with the original
	master key.</p>
      </item>
  </list>

  <section id="more" style="2column">
    <title>More about subkeys</title>
  </section>
</page>