Remove the apt-key manual page and add documentation to apt-secure

We move the user configuration section to the top of the manual
page as that is going to be what most are interested in and rewrite
it to cover all the modern ways to configure keys in a succinct
way.

5 files changed, 37 insertions, 271 deletions

diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
index 493c36c08..2df0ce721 100644
--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -84,7 +84,6 @@ add_docbook(apt-man MANPAGE ALL
         apt-extracttemplates.1.xml
         apt-ftparchive.1.xml
         apt-get.8.xml
-        apt-key.8.xml
         apt-mark.8.xml
         apt_preferences.5.xml
         apt-patterns.7.xml
diff --git a/doc/apt-key.8.xml b/doc/apt-key.8.xml
deleted file mode 100644
index c6c2d192e..000000000
--- a/doc/apt-key.8.xml
+++ /dev/null
@@ -1,246 +0,0 @@
-<?xml version="1.0" encoding="utf-8" standalone="no"?>
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
-  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
-<!ENTITY % aptent SYSTEM "apt.ent"> %aptent;
-<!ENTITY % aptverbatiment SYSTEM "apt-verbatim.ent"> %aptverbatiment;
-<!ENTITY % aptvendor SYSTEM "apt-vendor.ent"> %aptvendor;
-]>
-
-<refentry>
- <refentryinfo>
-   &apt-author.jgunthorpe;
-   &apt-author.team;
-   &apt-email;
-   &apt-product;
-   <!-- The last update date -->
-   <date>2024-02-20T00:00:00Z</date>
- </refentryinfo>
-
- <refmeta>
-   <refentrytitle>apt-key</refentrytitle>
-   <manvolnum>8</manvolnum>
-   <refmiscinfo class="manual">APT</refmiscinfo>
- </refmeta>
- 
- <!-- Man page title -->
- <refnamediv>
-    <refname>apt-key</refname>
-    <refpurpose>Deprecated APT key management utility</refpurpose>
- </refnamediv>
-
- &synopsis-command-apt-key;
-
- <refsect1><title>Description</title>
-   <para>
-   <command>apt-key</command> is used to manage the list of keys used
-   by apt to authenticate packages.  Packages which have been
-   authenticated using these keys will be considered trusted.
-   </para>
-   <para>
-   Use of <command>apt-key</command> is deprecated, except for the use of
-   <command>apt-key del</command> in maintainer scripts to remove existing
-   keys from the main keyring.
-   If such usage of <command>apt-key</command> is desired the additional
-   installation of the GNU Privacy Guard suite (packaged in
-   <package>gnupg</package>) is required.
-   </para>
-   <para>
-   apt-key(8) will last be available in Debian 12 and Ubuntu 24.04.
-   </para>
-</refsect1>
-
-<refsect1><title>Supported keyring files</title>
-<para>apt-key supports only the binary OpenPGP format (also known as "GPG key
-   public ring") in files with the "<literal>gpg</literal>" extension, not
-   the keybox database format introduced in newer &gpg; versions as default
-   for keyring files. Binary keyring files intended to be used with any apt
-   version should therefore always be created with <command>gpg --export</command>.
-</para>
-<para>Alternatively, if all systems which should be using the created keyring
-   have at least apt version >= 1.4 installed, you can use the ASCII armored
-   format with the "<literal>asc</literal>" extension instead which can be
-   created with <command>gpg --armor --export</command>.
-</para>
-</refsect1>
-
-<refsect1><title>Commands</title>
-   <variablelist>
-     <varlistentry><term><option>add</option> <option>&synopsis-param-filename;</option>  (deprecated)</term>
-     <listitem>
-     <para>
-       Add a new key to the list of trusted keys.
-       The key is read from the filename given with the parameter
-       &synopsis-param-filename; or if the filename is <literal>-</literal>
-       from standard input.
-     </para>
-     <para>
-     It is critical that keys added manually via <command>apt-key</command> are
-     verified to belong to the owner of the repositories they claim to be for
-     otherwise the &apt-secure; infrastructure is completely undermined.
-     </para>
-     <para>
-       <emphasis>Note</emphasis>: Instead of using this command a keyring
-       should be placed directly in the <filename>/etc/apt/trusted.gpg.d/</filename>
-       directory with a descriptive name and either "<literal>gpg</literal>" or
-       "<literal>asc</literal>" as file extension.
-     </para>
-     </listitem>
-     </varlistentry>
-
-     <varlistentry><term><option>del</option> <option>&synopsis-param-keyid;</option>  (mostly deprecated)</term>
-     <listitem>
-     <para>
-
-       Remove a key from the list of trusted keys.
-
-     </para>
-
-     </listitem>
-     </varlistentry>
-
-     <varlistentry><term><option>export</option> <option>&synopsis-param-keyid;</option>  (deprecated)</term>
-     <listitem>
-     <para>
-
-        Output the key &synopsis-param-keyid; to standard output.
-
-     </para>
-
-     </listitem>
-     </varlistentry>
-
-     <varlistentry><term><option>exportall</option>  (deprecated)</term>
-     <listitem>
-     <para>
-
-        Output all trusted keys to standard output.
-
-     </para>
-
-     </listitem>
-     </varlistentry>
-
-     <varlistentry><term><option>list</option>, <option>finger</option>  (deprecated)</term>
-     <listitem>
-     <para>
-
-       List trusted keys with fingerprints.
-
-     </para>
-
-     </listitem>
-     </varlistentry>
-
-     <varlistentry><term><option>adv</option>  (deprecated)</term>
-     <listitem>
-     <para>
-     Pass advanced options to gpg. With <command>adv --recv-key</command> you
-     can e.g. download key from keyservers directly into the trusted set of
-     keys. Note that there are <emphasis>no</emphasis> checks performed, so it is
-     easy to completely undermine the &apt-secure; infrastructure if used without
-     care.
-     </para>
-
-     </listitem>
-     </varlistentry>
-
-     <varlistentry><term><option>update</option> (deprecated)</term>
-     <listitem>
-     <para>
-       Update the local keyring with the archive keyring and remove from
-       the local keyring the archive keys which are no longer valid.
-       The archive keyring is shipped in the <literal>archive-keyring</literal> package of your
-       distribution, e.g. the &keyring-package; package in &keyring-distro;.
-     </para>
-     <para>
-       Note that a distribution does not need to and in fact should not use
-       this command any longer and instead ship keyring files in the
-       <filename>/etc/apt/trusted.gpg.d/</filename> directory directly as this
-       avoids a dependency on <package>gnupg</package> and it is easier to manage
-       keys by simply adding and removing files for maintainers and users alike.
-     </para>
-     </listitem>
-     </varlistentry>
-     
-     <varlistentry><term><option>net-update</option>  (deprecated)</term>
-     <listitem>
-     <para>
-
-       Perform an update working similarly to the <command>update</command> command above,
-       but get the archive keyring from a URI instead and validate it against a master key.
-
-       This requires an installed &wget; and an APT build configured to have
-       a server to fetch from and a master keyring to validate.
-
-       APT in Debian does not support this command, relying on
-       <command>update</command> instead, but Ubuntu's APT does.
-
-     </para>
-
-     </listitem>
-     </varlistentry>
-   </variablelist>
-</refsect1>
-
- <refsect1><title>Options</title>
-<para>Note that options need to be defined before the commands described in the previous section.</para>
-   <variablelist>
-      <varlistentry><term><option>--keyring</option> <option>&synopsis-param-filename;</option>  (deprecated)</term>
-      <listitem><para>With this option it is possible to specify a particular keyring
-      file the command should operate on. The default is that a command is executed
-      on the <filename>trusted.gpg</filename> file as well as on all parts in the
-      <filename>trusted.gpg.d</filename> directory, though <filename>trusted.gpg</filename>
-      is the primary keyring which means that e.g. new keys are added to this one.
-      </para></listitem>
-      </varlistentry>
-   </variablelist>
- </refsect1>
-
- <refsect1><title>Deprecation</title>
-
-	 <para>Except for using <command>apt-key del</command> in maintainer scripts, the use of <command>apt-key</command> is deprecated. This section shows how to replace existing use of <command>apt-key</command>.</para>
-
-<para>If your existing use of <command>apt-key add</command> looks like this:</para>
-<para><literal>wget -qO- https://myrepo.example/myrepo.asc | sudo apt-key add -</literal></para>
-<para>Then you can directly replace this with (though note the recommendation below):</para>
-<para><literal>wget -qO- https://myrepo.example/myrepo.asc | sudo tee /etc/apt/trusted.gpg.d/myrepo.asc</literal></para>
-<para>Make sure to use the "<literal>asc</literal>" extension for ASCII armored
-keys and the "<literal>gpg</literal>" extension for the binary OpenPGP
-format (also known as "GPG key public ring"). The binary OpenPGP format works
-for all apt versions, while the ASCII armored format works for apt version >=
-1.4.</para>
-<para><emphasis>Recommended:</emphasis> Instead of placing keys into the <filename>/etc/apt/trusted.gpg.d</filename>
-directory, you can place them anywhere on your filesystem by using the
-<literal>Signed-By</literal> option in your <literal>sources.list</literal> and
-pointing to the filename of the key. See &sources-list; for details.
-Since APT 2.4, <filename>/etc/apt/keyrings</filename> is provided as the recommended
-location for keys not managed by packages.
-When using a deb822-style sources.list, and with apt version >= 2.4, the
-<literal>Signed-By</literal> option can also be used to include the full ASCII
-armored keyring directly in the <literal>sources.list</literal> without an
-additional file.
-</para>
-
- </refsect1>
-
-
- <refsect1><title>Files</title>
-   <variablelist>
-
-     &file-trustedgpg;
-
-   </variablelist>
-
-</refsect1>
-
-<refsect1><title>See Also</title>
-<para>
-&apt-get;, &apt-secure;
-</para>
-</refsect1>
-
- &manbugs;
- &manauthor;
-
-</refentry>
-
diff --git a/doc/apt-secure.8.xml b/doc/apt-secure.8.xml
index 7e40a2b1c..0549011e4 100644
--- a/doc/apt-secure.8.xml
+++ b/doc/apt-secure.8.xml
@@ -60,6 +60,40 @@
    and &synaptic; support this authentication feature, so this manpage uses
    <literal>APT</literal> to refer to them all for simplicity only.
    </para>
+ </refsect1>
+
+<refsect1><title>User Configuration</title>
+  <para>
+    Keys should usually be included inside their corresponding <literal>.sources</literal>
+    by embedding the ASCII-armored key in the <literal>Signed-By</literal> option.
+    To do so, replace the empty line with a dot, and then indent all lines by two spaces.
+    See &sources-list; for more information.
+  </para>
+
+  <para>
+    Alternatively, keys may be placed in <filename>/etc/apt/keyrings</filename> for local keys,
+    or <filename>/usr/share/keyrings</filename> for keys managed by packages, and then referenced
+    by <literal>Signed-By: /etc/apt/keyrings/example-archive-keyring.asc</literal> option in a <literal>.sources</literal>
+    file or using <literal>deb [signed-by=/etc/apt/keyrings/example-archive-keyring.asc] ...</literal> in the legacy
+    <literal>.list</literal> format. This may be useful for APT versions prior to 2.4, which do not
+    support embedded keys. ASCII-armored keys must use an extension of <literal>.asc</literal>, and
+    unarmored keys an extension of <literal>.gpg</literal>.
+  </para>
+
+  <para>
+    To generate keys suitable for use in APT using GnuPG, you will need to use the 
+    <command>gpg --export-options export-minimal [--armor] --export</command> command.
+    Earlier solutions involving <command>--keyring file --import</command> no longer work
+    with recent GnuPG versions as they use a new internal format ("GPG keybox database").
+  </para>
+
+  <para>
+    Note that a default installation already contains all keys to securely
+    acquire packages from the default repositories, so managing keys
+    is only needed if third-party repositories are added.
+    The <command>extrepo</command> package can be used to manage several
+    external repositories with ease.
+  </para>
 </refsect1>
 
  <refsect1><title>Unsigned Repositories</title>
@@ -180,26 +214,6 @@
    </para>
 </refsect1>
 
-<refsect1><title>User Configuration</title>
-   <para>
-   <command>apt-key</command> is the program that manages the list of keys used
-   by APT to trust repositories. It can be used to add or remove keys as well
-   as list the trusted keys. Limiting which key(s) are able to sign which archive
-   is possible via the <option>Signed-By</option> in &sources-list;.
-   </para><para>
-   Note that a default installation already contains all keys to securely
-   acquire packages from the default repositories, so fiddling with
-   <command>apt-key</command> is only needed if third-party repositories are
-   added.
-   </para><para>
-   In order to add a new key you need to first download it
-   (you should make sure you are using a trusted communication channel
-   when retrieving it), add it with <command>apt-key</command> and
-   then run <command>apt-get update</command> so that apt can download
-   and verify the <filename>InRelease</filename> or <filename>Release.gpg</filename>
-   files from the archives you have configured.
-   </para>
-</refsect1>
 
 <refsect1><title>Repository Configuration</title>
    <para>
@@ -243,7 +257,7 @@
 
 <refsect1><title>See Also</title> 
 <para> 
-&apt-conf;, &apt-get;, &sources-list;, &apt-key;, &apt-ftparchive;,
+&apt-conf;, &apt-get;, &sources-list;, &apt-ftparchive;,
 &debsign;, &debsig-verify;, &gpg;
 </para>
 
diff --git a/doc/po4a.conf b/doc/po4a.conf
index 0798eac68..3cf4d5ea8 100644
--- a/doc/po4a.conf
+++ b/doc/po4a.conf
@@ -15,7 +15,6 @@
 [type: manpage] apt.8.xml $lang:$lang/apt.$lang.8.xml add_$lang:xml.add
 [type: manpage] apt-get.8.xml $lang:$lang/apt-get.$lang.8.xml add_$lang:xml.add
 [type: manpage] apt-cache.8.xml $lang:$lang/apt-cache.$lang.8.xml add_$lang:xml.add
-[type: manpage] apt-key.8.xml $lang:$lang/apt-key.$lang.8.xml add_$lang:xml.add
 [type: manpage] apt-mark.8.xml $lang:$lang/apt-mark.$lang.8.xml add_$lang:xml.add
 [type: manpage] apt-secure.8.xml $lang:$lang/apt-secure.$lang.8.xml add_$lang:xml.add
 [type: manpage] apt-cdrom.8.xml $lang:$lang/apt-cdrom.$lang.8.xml add_$lang:xml.add
diff --git a/doc/sources.list.5.xml b/doc/sources.list.5.xml
index 4fa7a245b..a463d4333 100644
--- a/doc/sources.list.5.xml
+++ b/doc/sources.list.5.xml
@@ -304,8 +304,8 @@ deb-src [ option1=value1 option2=value2 ] uri suite [component1] [component2] [.
 		and <filename>/etc/apt/keyrings</filename> for keyrings managed by the system operator.
 		If no keyring files are specified
 		the default is the <filename>trusted.gpg</filename> keyring and
-		all keyrings in the <filename>trusted.gpg.d/</filename> directory
-		(see <command>apt-key fingerprint</command>). If no fingerprint is
+		all keyrings in the <filename>trusted.gpg.d/</filename> directory.
+		If no fingerprint is
 		specified all keys in the keyrings are selected. A fingerprint will
 		accept also all signatures by a subkey of this key, if this isn't
 		desired an exclamation mark (<literal>!</literal>) can be appended to