68
52
<refname><command>&COMMANDNAME;</command></refname>
70
Sends encrypted passwords to authenticated Mandos clients
54
Gives encrypted passwords to authenticated Mandos clients
76
60
<command>&COMMANDNAME;</command>
77
<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>
78
<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>
79
<arg choice='opt'>--port<arg choice='plain'>PORT</arg></arg>
80
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
81
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
82
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
83
<arg choice='opt'>--debug</arg>
86
<command>&COMMANDNAME;</command>
87
<arg choice='opt'>-i<arg choice='plain'>IF</arg></arg>
88
<arg choice='opt'>-a<arg choice='plain'>ADDRESS</arg></arg>
89
<arg choice='opt'>-p<arg choice='plain'>PORT</arg></arg>
90
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
91
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
92
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
93
<arg choice='opt'>--debug</arg>
96
<command>&COMMANDNAME;</command>
97
<arg choice='plain'>--help</arg>
100
<command>&COMMANDNAME;</command>
101
<arg choice='plain'>--version</arg>
104
<command>&COMMANDNAME;</command>
105
<arg choice='plain'>--check</arg>
62
<arg choice="plain"><option>--interface
63
<replaceable>NAME</replaceable></option></arg>
64
<arg choice="plain"><option>-i
65
<replaceable>NAME</replaceable></option></arg>
69
<arg choice="plain"><option>--address
70
<replaceable>ADDRESS</replaceable></option></arg>
71
<arg choice="plain"><option>-a
72
<replaceable>ADDRESS</replaceable></option></arg>
76
<arg choice="plain"><option>--port
77
<replaceable>PORT</replaceable></option></arg>
78
<arg choice="plain"><option>-p
79
<replaceable>PORT</replaceable></option></arg>
82
<arg><option>--priority
83
<replaceable>PRIORITY</replaceable></option></arg>
85
<arg><option>--servicename
86
<replaceable>NAME</replaceable></option></arg>
88
<arg><option>--configdir
89
<replaceable>DIRECTORY</replaceable></option></arg>
91
<arg><option>--debug</option></arg>
93
<arg><option>--debuglevel
94
<replaceable>LEVEL</replaceable></option></arg>
96
<arg><option>--no-dbus</option></arg>
98
<arg><option>--no-ipv6</option></arg>
100
<arg><option>--no-restore</option></arg>
102
<arg><option>--statedir
103
<replaceable>DIRECTORY</replaceable></option></arg>
105
<arg><option>--socket
106
<replaceable>FD</replaceable></option></arg>
108
<arg><option>--foreground</option></arg>
110
<arg><option>--no-zeroconf</option></arg>
113
<command>&COMMANDNAME;</command>
115
<arg choice="plain"><option>--help</option></arg>
116
<arg choice="plain"><option>-h</option></arg>
120
<command>&COMMANDNAME;</command>
121
<arg choice="plain"><option>--version</option></arg>
124
<command>&COMMANDNAME;</command>
125
<arg choice="plain"><option>--check</option></arg>
107
127
</refsynopsisdiv>
109
129
<refsect1 id="description">
110
130
<title>DESCRIPTION</title>
112
132
<command>&COMMANDNAME;</command> is a server daemon which
113
133
handles incoming request for passwords for a pre-defined list of
114
client host computers. The Mandos server uses Zeroconf to
115
announce itself on the local network, and uses GnuTLS to
116
communicate securely with and to authenticate the clients.
117
Mandos uses IPv6 link-local addresses, since the clients are
118
assumed to not have any other addresses configured yet. Any
119
authenticated client is then given the pre-encrypted password
120
for that specific client.
134
client host computers. For an introduction, see
135
<citerefentry><refentrytitle>intro</refentrytitle>
136
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
137
uses Zeroconf to announce itself on the local network, and uses
138
TLS to communicate securely with and to authenticate the
139
clients. The Mandos server uses IPv6 to allow Mandos clients to
140
use IPv6 link-local addresses, since the clients will probably
141
not have any other addresses configured (see <xref
142
linkend="overview"/>). Any authenticated client is then given
143
the stored pre-encrypted password for that specific client.
125
147
<refsect1 id="purpose">
126
148
<title>PURPOSE</title>
129
150
The purpose of this is to enable <emphasis>remote and unattended
130
rebooting</emphasis> of any client host computer with an
131
<emphasis>encrypted root file system</emphasis>. The client
132
host computer should start a Mandos client in the initial RAM
133
disk environment, the Mandos client program communicates with
134
this server program to get an encrypted password, which is then
135
decrypted and used to unlock the encrypted root file system.
136
The client host computer can then continue its boot sequence
151
rebooting</emphasis> of client host computer with an
152
<emphasis>encrypted root file system</emphasis>. See <xref
153
linkend="overview"/> for details.
142
157
<refsect1 id="options">
143
158
<title>OPTIONS</title>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
161
<term><option>--help</option></term>
162
<term><option>-h</option></term>
150
165
Show a help message and exit
156
<term><literal>-i</literal>, <literal>--interface <replaceable>
157
IF</replaceable></literal></term>
160
Only announce the server and listen to requests on network
161
interface <replaceable>IF</replaceable>. Default is to
162
use all available interfaces.
168
<term><literal>-a</literal>, <literal>--address <replaceable>
169
ADDRESS</replaceable></literal></term>
172
If this option is used, the server will only listen to a
173
specific address. This must currently be an IPv6 address;
174
an IPv4 address can be specified using the
175
"<literal>::FFFF:192.0.2.3</literal>" syntax. Also, if a
176
link-local address is specified, an interface should be
177
set, since a link-local address is only valid on a single
178
interface. By default, the server will listen to all
185
<term><literal>-p</literal>, <literal>--port <replaceable>
186
PORT</replaceable></literal></term>
189
If this option is used, the server to bind to that
190
port. By default, the server will listen to an arbitrary
191
port given by the operating system.
197
<term><literal>--check</literal></term>
200
Run the server's self-tests. This includes any unit
171
<term><option>--interface</option>
172
<replaceable>NAME</replaceable></term>
173
<term><option>-i</option>
174
<replaceable>NAME</replaceable></term>
176
<xi:include href="mandos-options.xml" xpointer="interface"/>
181
<term><option>--address
182
<replaceable>ADDRESS</replaceable></option></term>
184
<replaceable>ADDRESS</replaceable></option></term>
186
<xi:include href="mandos-options.xml" xpointer="address"/>
192
<replaceable>PORT</replaceable></option></term>
194
<replaceable>PORT</replaceable></option></term>
196
<xi:include href="mandos-options.xml" xpointer="port"/>
201
<term><option>--check</option></term>
204
Run the server’s self-tests. This includes any unit
207
<term><literal>--debug</literal></term>
210
If the server is run in debug mode, it will run in the
211
foreground and print a lot of debugging information. The
212
default is <emphasis>not</emphasis> to run in debug mode.
218
<term><literal>--priority <replaceable>
219
PRIORITY</replaceable></literal></term>
222
GnuTLS priority string for the TLS handshake with the
224
<citerefentry><refentrytitle>gnutls_priority_init
225
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
226
for the syntax. The default is
227
"<literal>SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP</literal>".
228
<emphasis>Warning</emphasis>: changing this may make the
229
TLS handshake fail, making communication with clients
236
<term><literal>--servicename <replaceable>NAME</replaceable>
240
Zeroconf service name. The default is
241
"<literal>Mandos</literal>". You only need to change this
242
if you for some reason want to run more than one server on
243
the same <emphasis>host</emphasis>. If there are name
244
collisions on the same <emphasis>network</emphasis>, the
245
new server will automatically rename itself to "Mandos
252
<term><literal>--configdir <replaceable>DIR</replaceable>
211
<term><option>--debug</option></term>
213
<xi:include href="mandos-options.xml" xpointer="debug"/>
218
<term><option>--debuglevel
219
<replaceable>LEVEL</replaceable></option></term>
222
Set the debugging log level.
223
<replaceable>LEVEL</replaceable> is a string, one of
224
<quote><literal>CRITICAL</literal></quote>,
225
<quote><literal>ERROR</literal></quote>,
226
<quote><literal>WARNING</literal></quote>,
227
<quote><literal>INFO</literal></quote>, or
228
<quote><literal>DEBUG</literal></quote>, in order of
229
increasing verbosity. The default level is
230
<quote><literal>WARNING</literal></quote>.
236
<term><option>--priority <replaceable>
237
PRIORITY</replaceable></option></term>
239
<xi:include href="mandos-options.xml"
240
xpointer="priority_compat"/>
245
<term><option>--servicename
246
<replaceable>NAME</replaceable></option></term>
248
<xi:include href="mandos-options.xml"
249
xpointer="servicename"/>
254
<term><option>--configdir
255
<replaceable>DIRECTORY</replaceable></option></term>
256
258
Directory to search for configuration files. Default is
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
259
<quote><literal>/etc/mandos</literal></quote>. See
260
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
259
261
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
260
262
<refentrytitle>mandos-clients.conf</refentrytitle>
261
263
<manvolnum>5</manvolnum></citerefentry>.
267
<term><literal>--version</literal></term>
269
<term><option>--version</option></term>
270
272
Prints the program version and exit.
278
<term><option>--no-dbus</option></term>
280
<xi:include href="mandos-options.xml" xpointer="dbus"/>
282
See also <xref linkend="dbus_interface"/>.
288
<term><option>--no-ipv6</option></term>
290
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
295
<term><option>--no-restore</option></term>
297
<xi:include href="mandos-options.xml" xpointer="restore"/>
299
See also <xref linkend="persistent_state"/>.
305
<term><option>--statedir
306
<replaceable>DIRECTORY</replaceable></option></term>
308
<xi:include href="mandos-options.xml" xpointer="statedir"/>
313
<term><option>--socket
314
<replaceable>FD</replaceable></option></term>
316
<xi:include href="mandos-options.xml" xpointer="socket"/>
321
<term><option>--foreground</option></term>
323
<xi:include href="mandos-options.xml"
324
xpointer="foreground"/>
329
<term><option>--no-zeroconf</option></term>
331
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
338
<refsect1 id="overview">
339
<title>OVERVIEW</title>
340
<xi:include href="overview.xml"/>
342
This program is the server part. It is a normal server program
343
and will run in a normal system environment, not in an initial
344
<acronym>RAM</acronym> disk environment.
277
348
<refsect1 id="protocol">
278
349
<title>NETWORK PROTOCOL</title>
280
351
The Mandos server announces itself as a Zeroconf service of type
281
"<literal>_mandos._tcp</literal>". The Mandos client connects
282
to the announced address and port, and sends a line of text
283
where the first whitespace-separated field is the protocol
284
version, which currently is "<literal>1</literal>". The client
285
and server then start a TLS protocol handshake with a slight
286
quirk: the Mandos server program acts as a TLS "client" while
287
the connecting Mandos client acts as a TLS "server". The Mandos
288
client must supply an OpenPGP certificate, and the fingerprint
289
of this certificate is used by the Mandos server to look up (in
290
a list read from a file at start time) which binary blob to give
291
the client. No other authentication or authorization is done by
352
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
353
client connects to the announced address and port, and sends a
354
line of text where the first whitespace-separated field is the
355
protocol version, which currently is
356
<quote><literal>1</literal></quote>. The client and server then
357
start a TLS protocol handshake with a slight quirk: the Mandos
358
server program acts as a TLS <quote>client</quote> while the
359
connecting Mandos client acts as a TLS <quote>server</quote>.
360
The Mandos client must supply an OpenPGP certificate, and the
361
fingerprint of this certificate is used by the Mandos server to
362
look up (in a list read from <filename>clients.conf</filename>
363
at start time) which binary blob to give the client. No other
364
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
367
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
369
<entry>Mandos Client</entry>
297
370
<entry>Direction</entry>
320
395
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
396
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
400
<entry><-<!-- ← --></entry>
326
401
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
403
</tbody></tgroup></table>
406
<refsect1 id="checking">
407
<title>CHECKING</title>
409
The server will, by default, continually check that the clients
410
are still up. If a client has not been confirmed as being up
411
for some time, the client is assumed to be compromised and is no
412
longer eligible to receive the encrypted password. (Manual
413
intervention is required to re-enable a client.) The timeout,
414
extended timeout, checker program, and interval between checks
415
can be configured both globally and per client; see
416
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
417
<manvolnum>5</manvolnum></citerefentry>.
421
<refsect1 id="approval">
422
<title>APPROVAL</title>
424
The server can be configured to require manual approval for a
425
client before it is sent its secret. The delay to wait for such
426
approval and the default action (approve or deny) can be
427
configured both globally and per client; see <citerefentry>
428
<refentrytitle>mandos-clients.conf</refentrytitle>
429
<manvolnum>5</manvolnum></citerefentry>. By default all clients
430
will be approved immediately without delay.
433
This can be used to deny a client its secret if not manually
434
approved within a specified time. It can also be used to make
435
the server delay before giving a client its secret, allowing
436
optional manual denying of this specific client.
331
441
<refsect1 id="logging">
332
442
<title>LOGGING</title>
334
The server will log a lot of information with various severity
336
<citerefentry><refentrytitle>syslog</refentrytitle>
337
<manvolnum>8</manvolnum></citerefentry>. With the
444
The server will send log message with various severity levels to
445
<filename class="devicefile">/dev/log</filename>. With the
338
446
<option>--debug</option> option, it will log even more messages,
339
447
and also show them on the console.
451
<refsect1 id="persistent_state">
452
<title>PERSISTENT STATE</title>
454
Client settings, initially read from
455
<filename>clients.conf</filename>, are persistent across
456
restarts, and run-time changes will override settings in
457
<filename>clients.conf</filename>. However, if a setting is
458
<emphasis>changed</emphasis> (or a client added, or removed) in
459
<filename>clients.conf</filename>, this will take precedence.
463
<refsect1 id="dbus_interface">
464
<title>D-BUS INTERFACE</title>
466
The server will by default provide a D-Bus system bus interface.
467
This interface will only be accessible by the root user or a
468
Mandos-specific user, if such a user exists. For documentation
469
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
473
<refsect1 id="exit_status">
344
474
<title>EXIT STATUS</title>
347
477
critical error is encountered.
481
<refsect1 id="environment">
482
<title>ENVIRONMENT</title>
485
<term><envar>PATH</envar></term>
488
To start the configured checker (see <xref
489
linkend="checking"/>), the server uses
490
<filename>/bin/sh</filename>, which in turn uses
491
<varname>PATH</varname> to search for matching commands if
492
an absolute path is not given. See <citerefentry>
493
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
501
<refsect1 id="files">
352
502
<title>FILES</title>
356
<filename>/etc/mandos/mandos.conf</filename> See <citerefentry>
357
<refentrytitle>mandos.conf</refentrytitle>
358
<manvolnum>5</manvolnum></citerefentry>.
361
<filename>/etc/mandos/clients.conf</filename> See <citerefentry>
504
Use the <option>--configdir</option> option to change where
505
<command>&COMMANDNAME;</command> looks for its configurations
506
files. The default file names are listed here.
510
<term><filename>/etc/mandos/mandos.conf</filename></term>
513
Server-global settings. See
514
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
515
<manvolnum>5</manvolnum></citerefentry> for details.
520
<term><filename>/etc/mandos/clients.conf</filename></term>
523
List of clients and client-specific settings. See
524
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
525
<manvolnum>5</manvolnum></citerefentry> for details.
530
<term><filename>/run/mandos.pid</filename></term>
533
The file containing the process id of the
534
<command>&COMMANDNAME;</command> process started last.
535
<emphasis >Note:</emphasis> If the <filename
536
class="directory">/run</filename> directory does not
537
exist, <filename>/var/run/mandos.pid</filename> will be
543
<term><filename class="devicefile">/dev/log</filename></term>
547
class="directory">/var/lib/mandos</filename></term>
550
Directory where persistent state will be saved. Change
551
this with the <option>--statedir</option> option. See
552
also the <option>--no-restore</option> option.
557
<term><filename>/dev/log</filename></term>
560
The Unix domain socket to where local syslog messages are
566
<term><filename>/bin/sh</filename></term>
569
This is used to start the configured checker command for
570
each client. See <citerefentry>
362
571
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
572
<manvolnum>5</manvolnum></citerefentry> for details.
372
579
<refsect1 id="bugs">
373
580
<title>BUGS</title>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
582
This server might, on especially fatal errors, emit a Python
583
backtrace. This could be considered a feature.
586
There is no fine-grained control over logging and debug output.
589
This server does not check the expire time of clients’ OpenPGP
594
<refsect1 id="example">
595
<title>EXAMPLE</title>
598
Normal invocation needs no options:
601
<userinput>&COMMANDNAME;</userinput>
606
Run the server in debug mode, read configuration files from
607
the <filename class="directory">~/mandos</filename> directory,
608
and use the Zeroconf service name <quote>Test</quote> to not
609
collide with any other official Mandos server on this host:
613
<!-- do not wrap this line -->
614
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
620
Run the server normally, but only listen to one interface and
621
only on the link-local address on that interface:
625
<!-- do not wrap this line -->
626
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
632
<refsect1 id="security">
385
633
<title>SECURITY</title>
634
<refsect2 id="server">
635
<title>SERVER</title>
637
Running this <command>&COMMANDNAME;</command> server program
638
should not in itself present any security risk to the host
639
computer running it. The program switches to a non-root user
643
<refsect2 id="clients">
644
<title>CLIENTS</title>
646
The server only gives out its stored data to clients which
647
does have the OpenPGP key of the stored fingerprint. This is
648
guaranteed by the fact that the client sends its OpenPGP
649
public key in the TLS handshake; this ensures it to be
650
genuine. The server computes the fingerprint of the key
651
itself and looks up the fingerprint in its list of
652
clients. The <filename>clients.conf</filename> file (see
653
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
654
<manvolnum>5</manvolnum></citerefentry>)
655
<emphasis>must</emphasis> be made non-readable by anyone
656
except the user starting the server (usually root).
659
As detailed in <xref linkend="checking"/>, the status of all
660
client computers will continually be checked and be assumed
661
compromised if they are gone for too long.
664
For more details on client-side security, see
665
<citerefentry><refentrytitle>mandos-client</refentrytitle>
666
<manvolnum>8mandos</manvolnum></citerefentry>.
390
671
<refsect1 id="see_also">
391
672
<title>SEE ALSO</title>
392
<itemizedlist spacing="compact">
394
<citerefentry><refentrytitle>password-request</refentrytitle>
395
<manvolnum>8mandos</manvolnum></citerefentry>
399
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
400
<manvolnum>8mandos</manvolnum></citerefentry>
404
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
408
<ulink url="http://www.avahi.org/">Avahi</ulink>
413
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
417
<citation>RFC 4880: <citetitle>OpenPGP Message
418
Format</citetitle></citation>
422
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
423
Transport Layer Security</citetitle></citation>
427
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
428
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
429
Unicast Addresses</citation>
674
<citerefentry><refentrytitle>intro</refentrytitle>
675
<manvolnum>8mandos</manvolnum></citerefentry>,
676
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
677
<manvolnum>5</manvolnum></citerefentry>,
678
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
679
<manvolnum>5</manvolnum></citerefentry>,
680
<citerefentry><refentrytitle>mandos-client</refentrytitle>
681
<manvolnum>8mandos</manvolnum></citerefentry>,
682
<citerefentry><refentrytitle>sh</refentrytitle>
683
<manvolnum>1</manvolnum></citerefentry>
688
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
692
Zeroconf is the network protocol standard used by clients
693
for finding this Mandos server on the local network.
699
<ulink url="http://www.avahi.org/">Avahi</ulink>
703
Avahi is the library this server calls to implement
704
Zeroconf service announcements.
710
<ulink url="http://gnutls.org/">GnuTLS</ulink>
714
GnuTLS is the library this server uses to implement TLS for
715
communicating securely with the client, and at the same time
716
confidently get the client’s public OpenPGP key.
722
RFC 4291: <citetitle>IP Version 6 Addressing
723
Architecture</citetitle>
728
<term>Section 2.2: <citetitle>Text Representation of
729
Addresses</citetitle></term>
730
<listitem><para/></listitem>
733
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
734
Address</citetitle></term>
735
<listitem><para/></listitem>
738
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
739
Addresses</citetitle></term>
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The clients use IPv6 link-local addresses, which are
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immediately usable since a link-local addresses is
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automatically assigned to a network interfaces when it
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RFC 5246: <citetitle>The Transport Layer Security (TLS)
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Protocol Version 1.2</citetitle>
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TLS 1.2 is the protocol implemented by GnuTLS.
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RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
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The data sent to clients is binary encrypted OpenPGP data.
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RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
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Security (TLS) Authentication</citetitle>
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This is implemented by GnuTLS and used by this server so
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that OpenPGP keys can be used.
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