<?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 % aptent SYSTEM "apt.ent"> %aptent;
+<!ENTITY % aptverbatiment SYSTEM "apt-verbatim.ent"> %aptverbatiment;
+<!ENTITY % aptvendor SYSTEM "apt-vendor.ent"> %aptvendor;
]>
<refentry>
&apt-email;
&apt-product;
<!-- The last update date -->
- <date>2012-05-21T00:00:00Z</date>
+ <date>2012-06-09T00:00:00Z</date>
</refentryinfo>
<refmeta>
</para>
<para>
- If a package comes from a archive without a signature or with a
- signature that apt does not have a key for that package is
- considered untrusted and installing it will result in a big
+ If a package comes from a archive without a signature, or with a
+ signature that apt does not have a key for, that package is
+ considered untrusted, and installing it will result in a big
warning. <command>apt-get</command> will currently only warn
- for unsigned archives, future releases might force all sources
+ for unsigned archives; future releases might force all sources
to be verified before downloading packages from them.
</para>
<para>
The chain of trust from an apt archive to the end user is made up of
- different steps. <command>apt-secure</command> is the last step in
- this chain, trusting an archive does not mean that the packages
- that you trust it do not contain malicious code but means that you
- trust the archive maintainer. It's the archive maintainer
- responsibility to ensure that the archive integrity is correct.
+ several steps. <command>apt-secure</command> is the last step in
+ this chain; trusting an archive does not mean that you trust its
+ packages not to contain malicious code, but means that you
+ trust the archive maintainer. It's the archive maintainer's
+ responsibility to ensure that the archive's integrity is preserved.
</para>
<para>apt-secure does not review signatures at a
<para>
The chain of trust in Debian starts when a maintainer uploads a new
- package or a new version of a package to the Debian archive. This
- upload in order to become effective needs to be signed by a key of
- a maintainer within the Debian maintainer's keyring (available in
- the debian-keyring package). Maintainer's keys are signed by
+ package or a new version of a package to the Debian archive. In
+ order to become effective, this upload needs to be signed by a key
+ contained in the Debian Maintainers keyring (available in
+ the debian-keyring package). Maintainers' keys are signed by
other maintainers following pre-established procedures to
ensure the identity of the key holder.
</para>
<para>
Once the uploaded package is verified and included in the archive,
- the maintainer signature is stripped off, an MD5 sum of the package
- is computed and put in the Packages file. The MD5 sum of all of the
- packages files are then computed and put into the Release file. The
- Release file is then signed by the archive key (which is created
- once a year) and distributed through the FTP server. This key is
- also on the Debian keyring.
+ the maintainer signature is stripped off, and checksums of the package
+ are computed and put in the Packages file. The checksums of all of the
+ Packages files are then computed and put into the Release file. The
+ Release file is then signed by the archive key for this &keyring-distro; release,
+ and distributed alongside the packages and the Packages files on
+ &keyring-distro; mirrors. The keys are in the &keyring-distro; archive keyring
+ available in the &keyring-package; package.
</para>
<para>
- Any end user can check the signature of the Release file, extract the MD5
- sum of a package from it and compare it with the MD5 sum of the
- package he downloaded. Prior to version 0.6 only the MD5 sum of the
- downloaded Debian package was checked. Now both the MD5 sum and the
- signature of the Release file are checked.
+ End users can check the signature of the Release file, extract a checksum
+ of a package from it and compare it with the checksum of the package
+ they downloaded by hand - or rely on APT doing this automatically.
</para>
<para>Notice that this is distinct from checking signatures on a
<itemizedlist>
<listitem><para><literal>Network "man in the middle"
- attacks</literal>. Without signature checking, a malicious
- agent can introduce himself in the package download process and
+ attacks</literal>. Without signature checking, malicious
+ agents can introduce themselves into the package download process and
provide malicious software either by controlling a network
element (router, switch, etc.) or by redirecting traffic to a
- rogue server (through arp or DNS spoofing
+ rogue server (through ARP or DNS spoofing
attacks).</para></listitem>
<listitem><para><literal>Mirror network compromise</literal>.
<refsect1><title>User configuration</title>
<para>
<command>apt-key</command> is the program that manages the list
- of keys used by apt. It can be used to add or remove keys although
- an installation of this release will automatically provide the
+ of keys used by apt. It can be used to add or remove keys, although
+ an installation of this release will automatically contain the
default Debian archive signing keys used in the Debian package
repositories.
</para>
</itemizedlist>
- <para>Whenever the contents of the archive changes (new packages
+ <para>Whenever the contents of the archive change (new packages
are added or removed) the archive maintainer has to follow the
- first two steps previously outlined.</para>
+ first two steps outlined above.</para>
</refsect1>
<refsect1><title>See Also</title>
<para>
&apt-conf;, &apt-get;, &sources-list;, &apt-key;, &apt-ftparchive;,
-&debsign; &debsig-verify;, &gpg;
+&debsign;, &debsig-verify;, &gpg;
</para>
<para>For more background information you might want to review the
projects / apt.git / blobdiff