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GPG-AGENT(1)		       GNU Privacy Guard		  GPG-AGENT(1)

NAME
       gpg-agent - Secret key management for GnuPG

SYNOPSIS
       gpg-agent [--homedir dir] [--options file] [options]
       gpg-agent [--homedir dir] [--options file] [options] --server
       gpg-agent  [--homedir  dir]  [--options	file] [options]	--daemon [com-
       mand_line]

DESCRIPTION
       gpg-agent is a daemon to	manage	secret	(private)  keys	 independently
       from  any  protocol.  It	is used	as a backend for gpg and gpgsm as well
       as for a	couple of other	utilities.

       The usual way to	run the	agent is from the ~/.xsession file:

	 eval $(gpg-agent --daemon)

       If you don't use	an X server, you can also put this into	 your  regular
       startup file ~/.profile or .bash_profile.  It is	best not to run	multi-
       ple instance of the gpg-agent, so you should make sure that only	one is
       running:	gpg-agent uses an environment variable to inform clients about
       the communication parameters. You can write the content of  this	 envi-
       ronment	variable  to  a	file so	that you can test for a	running	agent.
       Here is an example using	Bourne shell syntax:

	 gpg-agent --daemon --enable-ssh-support \
		   --write-env-file "${HOME}/.gpg-agent-info"

       This code should	only be	run once per user session to initially fire up
       the agent.  In the example the optional support for the included	Secure
       Shell agent is enabled and the information about	the agent  is  written
       to  a file in the HOME directory.  Note that by running gpg-agent with-
       out arguments you may test whether an agent is already running; however
       such a test may lead to a race condition, thus it is not	suggested.

       The second script needs to be run for each interactive session:

	 if [ -f "${HOME}/.gpg-agent-info" ]; then
	   . "${HOME}/.gpg-agent-info"
	   export GPG_AGENT_INFO
	   export SSH_AUTH_SOCK
	 fi

       It  reads  the  data out	of the file and	exports	the variables.	If you
       don't use Secure	Shell, you don't need the last two export statements.

       You should always add the following lines to your .bashrc  or  whatever
       initialization file is used for all shell invocations:

	 GPG_TTY=$(tty)
	 export	GPG_TTY

       It is important that this environment variable always reflects the out-
       put of the tty command.	For W32	systems	this option is not required.

       Please make sure	that a proper pinentry program has been	installed  un-
       der  the	default	filename (which	is system dependant) or	use the	option
       pinentry-program	to specify the full name of that program.  It is often
       useful  to  install a symbolic link from	the actual used	pinentry (e.g.
       `/usr/bin/pinentry-gtk')	to the	expected  one  (e.g.  `/usr/bin/pinen-
       try').

COMMANDS
       Commands	 are  not  distinguished from options except for the fact that
       only one	command	is allowed.

       --version
	      Print the	program	version	and licensing information.  Note  that
	      you cannot abbreviate this command.

       --help

       -h     Print  a	usage message summarizing the most useful command-line
	      options.	Note that you cannot abbreviate	this command.

       --dump-options
	      Print a list of all available options and	commands.   Note  that
	      you cannot abbreviate this command.

       --server
	      Run  in server mode and wait for commands	on the stdin.  The de-
	      fault mode is to create a	socket and listen for commands there.

       --daemon	[command line]
	      Start the	gpg-agent as a daemon; that is,	 detach	 it  from  the
	      console  and run it in the background.  Because gpg-agent	prints
	      out important information	required for further use, a common way
	      of  invoking  gpg-agent  is: eval	$(gpg-agent --daemon) to setup
	      the environment variables.  The option --write-env-file  is  an-
	      other way	commonly used to do this.  Yet another way is creating
	      a	new process  as	 a  child  of  gpg-agent:  gpg-agent  --daemon
	      /bin/sh.	 This  way  you	 get  a	new shell with the environment
	      setup properly; if you exit from this  shell,  gpg-agent	termi-
	      nates as well.

OPTIONS
       --options file
	      Reads  configuration  from file instead of from the default per-
	      user configuration file.	 The  default  configuration  file  is
	      named  `gpg-agent.conf'  and  expected in	the `.gnupg' directory
	      directly below the home directory	of the user.

       --homedir dir
	      Set the name of the home directory to dir. If this option	is not
	      used,  the  home	directory  defaults to `~/.gnupg'.  It is only
	      recognized when given on the command line.   It  also  overrides
	      any  home	 directory  stated  through  the  environment variable
	      `GNUPGHOME' or (on W32 systems) by means of the  Registry	 entry
	      HKCU\Software\GNU\GnuPG:HomeDir.

       -v

       --verbose
	      Outputs  additional information while running.  You can increase
	      the verbosity by giving several verbose commands to gpgsm,  such
	      as '-vv'.

       -q

       --quiet
	      Try to be	as quiet as possible.

       --batch
	      Don't  invoke  a	pinentry or do any other thing requiring human
	      interaction.

       --faked-system-time epoch
	      This option is only useful for testing; it sets the system  time
	      back  or	forth  to epoch	which is the number of seconds elapsed
	      since the	year 1970.

       --debug-level level
	      Select the debug level for investigating problems. level may  be
	      a	numeric	value or a keyword:

	      none   No	 debugging at all.  A value of less than 1 may be used
		     instead of	the keyword.

	      basic  Some basic	debug messages.	 A value between 1 and	2  may
		     be	used instead of	the keyword.

	      advanced
		     More verbose debug	messages.  A value between 3 and 5 may
		     be	used instead of	the keyword.

	      expert Even more detailed	messages.  A value between 6 and 8 may
		     be	used instead of	the keyword.

	      guru   All  of  the  debug messages you can get. A value greater
		     than 8 may	be used	instead	of the keyword.	 The  creation
		     of	 hash  tracing files is	only enabled if	the keyword is
		     used.

       How these messages are mapped to	the  actual  debugging	flags  is  not
       specified  and may change with newer releases of	this program. They are
       however carefully selected to best aid in debugging.

       --debug flags
	      This option is only useful for debugging and the	behaviour  may
	      change  at  any  time without notice.  FLAGS are bit encoded and
	      may be given in usual C-Syntax. The currently defined bits are:

	      0	(1)  X.509 or OpenPGP protocol related data

	      1	(2)  values of big number integers

	      2	(4)  low level crypto operations

	      5	(32) memory allocation

	      6	(64) caching

	      7	(128)
		     show memory statistics.

	      9	(512)
		     write hashed data to files	named dbgmd-000*

	      10 (1024)
		     trace Assuan protocol

	      12 (4096)
		     bypass all	certificate validation

       --debug-all
	      Same as --debug=0xffffffff

       --debug-wait n
	      When running in server mode, wait	n seconds before entering  the
	      actual  processing  loop	and print the pid.  This gives time to
	      attach a debugger.

       --no-detach
	      Don't detach the process from the	console.  This is mainly  use-
	      ful for debugging.

       -s

       --sh

       -c

       --csh  Format  the info output in daemon	mode for use with the standard
	      Bourne shell or the C-shell respectively.	  The  default	is  to
	      guess  it	 based on the environment variable SHELL which is cor-
	      rect in almost all cases.

       --write-env-file	file
	      Often it is required to connect to the agent from	a process  not
	      being an inferior	of gpg-agent and thus the environment variable
	      with the socket name is not available.  To help setting up those
	      variables	 in  other  sessions, this option may be used to write
	      the information into file.  If file is not specified the default
	      name  `${HOME}/.gpg-agent-info'  will  be	 used.	 The format is
	      suitable to be evaluated by a Bourne shell like in  this	simple
	      example:

	 eval $(cat file)
	 eval $(cut -d=	-f 1 < file | xargs echo export)

       --no-grab
	      Tell  the	pinentry not to	grab the keyboard and mouse.  This op-
	      tion should in general not be used to avoid X-sniffing attacks.

       --log-file file
	      Append all logging output	to file.  This is very helpful in see-
	      ing  what	 the agent actually does.  If neither a	log file nor a
	      log file descriptor has been set on a Windows platform, the Reg-
	      istry  entry  HKCU\Software\GNU\GnuPG:DefaultLogFile, if set, is
	      used to specify the logging output.

       --allow-mark-trusted
	      Allow clients to mark keys as trusted, i.e. put  them  into  the
	      `trustlist.txt' file.  This is by	default	not allowed to make it
	      harder for users to inadvertently	accept Root-CA keys.

       --no-allow-external-cache
	      Tell Pinentry not	to enable features which use an	external cache
	      for passphrases.

	      Some  desktop environments prefer	to unlock all credentials with
	      one master password and may have installed a Pinentry which  em-
	      ploys  an	 additional external cache to implement	such a policy.
	      By using this option the Pinentry	is advised not to make use  of
	      such  a  cache and instead always	ask the	user for the requested
	      passphrase.

       --ignore-cache-for-signing
	      This option will let gpg-agent bypass the	passphrase  cache  for
	      all  signing  operation.	 Note that there is also a per-session
	      option to	control	this behaviour but this	 command  line	option
	      takes precedence.

       --default-cache-ttl n
	      Set  the	time a cache entry is valid to n seconds.  The default
	      is 600 seconds.

       --default-cache-ttl-ssh n
	      Set the time a cache entry used for SSH keys is valid to n  sec-
	      onds.  The default is 1800 seconds.

       --max-cache-ttl n
	      Set the maximum time a cache entry is valid to n seconds.	 After
	      this time	a cache	entry will be expired even if it has been  ac-
	      cessed  recently	or  has	 been set using	gpg-preset-passphrase.
	      The default is 2 hours (7200 seconds).

       --max-cache-ttl-ssh n
	      Set the maximum time a cache entry used for SSH keys is valid to
	      n	 seconds.   After this time a cache entry will be expired even
	      if it has	been accessed recently or has been set using  gpg-pre-
	      set-passphrase.  The default is 2	hours (7200 seconds).

       --enforce-passphrase-constraints
	      Enforce  the  passphrase constraints by not allowing the user to
	      bypass them using	the ``Take it anyway'' button.

       --min-passphrase-len n
	      Set the minimal length of	a passphrase.	When  entering	a  new
	      passphrase  shorter than this value a warning will be displayed.
	      Defaults to 8.

       --min-passphrase-nonalpha n
	      Set the minimal number of	digits or special characters  required
	      in  a passphrase.	 When entering a new passphrase	with less than
	      this number of digits or special characters a  warning  will  be
	      displayed.  Defaults to 1.

       --check-passphrase-pattern file
	      Check  the  passphrase  against the pattern given	in file.  When
	      entering a new passphrase	matching one of	these pattern a	 warn-
	      ing will be displayed. file should be an absolute	filename.  The
	      default is not to	use any	pattern	file.

	      Security note: It	is known that checking a passphrase against  a
	      list  of	pattern	 or  even against a complete dictionary	is not
	      very effective to	enforce	good  passphrases.   Users  will  soon
	      figure  up  ways to bypass such a	policy.	 A better policy is to
	      educate users on good security behavior and optionally to	run  a
	      passphrase  cracker  regularly on	all users passphrases to catch
	      the very simple ones.

       --max-passphrase-days n
	      Ask the user to change the passphrase  if	 n  days  have	passed
	      since  the  last	change.	 With --enforce-passphrase-constraints
	      set the user may not bypass this check.

       --enable-passphrase-history
	      This option does nothing yet.

       --pinentry-program filename
	      Use program filename as the PIN entry.  The default is installa-
	      tion dependent.

       --pinentry-touch-file filename
	      By default the filename of the socket gpg-agent is listening for
	      requests is passed to Pinentry, so that it can touch  that  file
	      before  exiting (it does this only in curses mode).  This	option
	      changes the file passed to Pinentry to  filename.	  The  special
	      name  /dev/null  may be used to completely disable this feature.
	      Note that	Pinentry will not  create  that	 file,	it  will  only
	      change the modification and access time.

       --scdaemon-program filename
	      Use  program  filename  as the Smartcard daemon.	The default is
	      installation dependent and can be	shown with  the	 gpgconf  com-
	      mand.

       --disable-scdaemon
	      Do  not  make use	of the scdaemon	tool.  This option has the ef-
	      fect of disabling	the ability to do smartcard operations.	 Note,
	      that  enabling  this  option at runtime does not kill an already
	      forked scdaemon.

       --use-standard-socket

       --no-use-standard-socket
	      By enabling this option gpg-agent	 will  listen  on  the	socket
	      named `S.gpg-agent', located in the home directory, and not cre-
	      ate a random socket below	a temporary directory.	Tools connect-
	      ing to gpg-agent should first try	to connect to the socket given
	      in environment variable GPG_AGENT_INFO and  then	fall  back  to
	      this  socket.  This option may not be used if the	home directory
	      is mounted on a remote file system which does not	 support  spe-
	      cial  files  like	 fifos or sockets.  Note, that --use-standard-
	      socket is	the default on Windows systems.	 The  default  may  be
	      changed  at  build  time.	  It  is  possible  to test at runtime
	      whether the agent	has been configured for	use with the  standard
	      socket  by issuing the command gpg-agent --use-standard-socket-p
	      which returns success if the standard socket option has been en-
	      abled.

       --display string

       --ttyname string

       --ttytype string

       --lc-ctype string

       --lc-messages string

       --xauthority string
	      These options are	used with the server mode to pass localization
	      information.

       --keep-tty

       --keep-display
	      Ignore requests to change	the current tty	or X  window  system's
	      DISPLAY  variable	 respectively.	 This  is  useful  to lock the
	      pinentry to pop up at the	tty or display you started the agent.

       --enable-ssh-support

	      Enable the OpenSSH Agent protocol.

	      In this mode of operation, the agent does	not only implement the
	      gpg-agent	 protocol, but also the	agent protocol used by OpenSSH
	      (through a separate socket).  Consequently, it should be	possi-
	      ble  to  use the gpg-agent as a drop-in replacement for the well
	      known ssh-agent.

	      SSH Keys,	which are to be	used through the  agent,  need	to  be
	      added  to	 the  gpg-agent	initially through the ssh-add utility.
	      When a key is added, ssh-add will	ask for	the  password  of  the
	      provided	key  file and send the unprotected key material	to the
	      agent; this causes the gpg-agent to ask for a passphrase,	 which
	      is  to be	used for encrypting the	newly received key and storing
	      it in a gpg-agent	specific directory.

	      Once a key has been added	to the gpg-agent this  way,  the  gpg-
	      agent will be ready to use the key.

	      Note:  in	 case  the gpg-agent receives a	signature request, the
	      user might need to be prompted for a passphrase, which is	neces-
	      sary  for	decrypting the stored key.  Since the ssh-agent	proto-
	      col does not contain a mechanism for telling the agent on	 which
	      display/terminal it is running, gpg-agent's ssh-support will use
	      the TTY or X display  where  gpg-agent  has  been	 started.   To
	      switch  this  display  to	the current one, the following command
	      may be used:

	 gpg-connect-agent updatestartuptty /bye

       Although	all GnuPG components try to start  the	gpg-agent  as  needed,
       this  is	 not  possible	for  the ssh support because ssh does not know
       about it.  Thus if no GnuPG tool	which accesses the agent has been run,
       there  is no guarantee that ssh is abale	to use gpg-agent for authenti-
       cation.	To fix this you	may start gpg-agent if needed using this  sim-
       ple command:

	 gpg-connect-agent /bye

       Adding the --verbose shows the progress of starting the agent.

       All  the	long options may also be given in the configuration file after
       stripping off the two leading dashes.

EXAMPLES
       The usual way to	invoke gpg-agent is

	 $ eval	$(gpg-agent --daemon)

       An alternative way is by	replacing ssh-agent with  gpg-agent.   If  for
       example	ssh-agent  is  started as part of the Xsession initialization,
       you may simply replace ssh-agent	by a script like:

	 #!/bin/sh

	 exec /usr/local/bin/gpg-agent --enable-ssh-support --daemon \
	       --write-env-file	${HOME}/.gpg-agent-info	"$@"

       and add something like (for Bourne shells)

	   if [	-f "${HOME}/.gpg-agent-info" ];	then
	     . "${HOME}/.gpg-agent-info"
	     export GPG_AGENT_INFO
	     export SSH_AUTH_SOCK
	   fi

       to your shell initialization file (e.g. `~/.bashrc').

FILES
       There are a few configuration files needed for  the  operation  of  the
       agent.  By  default they	may all	be found in the	current	home directory
       (see: [option --homedir]).

       gpg-agent.conf
		This is	the standard configuration file	read by	gpg-agent on
		startup.  It may contain any valid long	option;	the leading
		two dashes may not be entered and the option may not be	abbre-
	      viated.
		This file is also read after a SIGHUP however only a few
		options	 will  actually	have an	effect.	 This default name may
	      be
		changed	on the command line (see: [option --options]).
		You should backup this file.

       trustlist.txt
		This is	the list of trusted  keys.   You  should  backup  this
	      file.

		Comment	 lines,	 indicated  by a leading hash mark, as well as
	      empty
		lines are ignored.  To mark a key as trusted you need to enter
	      its
		fingerprint  followed  by  a  space  and  a  capital letter S.
	      Colons
		may optionally be used to separate the bytes of	a fingerprint;
	      this
		allows	to  cut	 and  paste the	fingerprint from a key listing
	      output.  If
		the line is prefixed with a ! the key is explicitly marked as
		not trusted.

		Here is	an example where two keys  are	marked	as  ultimately
	      trusted
		and one	as not trusted:

		.RS 2
		# CN=Wurzel ZS 3,O=Intevation GmbH,C=DE
		A6935DD34EF3087973C706FC311AA2CCF733765B S

		# CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE
		DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S

		# CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE
		!14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S
		.fi

       Before entering a key into this file, you need to ensure	its
       authenticity.  How to do	this depends on	your organisation; your
       administrator might have	already	entered	those keys which are deemed
       trustworthy enough into this file.  Places where	to look	for the
       fingerprint of a	root certificate are letters received from the CA or
       the website of the CA (after making 100%	sure that this is indeed the
       website of that CA).  You may want to consider allowing interactive
       updates of this file by using the see: [option --allow-mark-trusted].
       This is however not as secure as	maintaining this file manually.	 It is
       even advisable to change	the permissions	to read-only so	that this file
       can't be	changed	inadvertently.

       As a special feature a line include-default will	include	a global
       list of trusted certificates (e.g. `/etc/gnupg/trustlist.txt').
       This global list	is also	used if	the local list is not available.

       It is possible to add further flags after the S for use by the
       caller:

	      relax  Relax checking of some root certificate requirements.  As of now this
		     flag allows the use of root certificates with a missing basicConstraints
		     attribute (despite	that it	is a MUST for CA certificates) and disables
		     CRL checking for the root certificate.

	      cm     If	validation of a	certificate finally issued by a	CA with	this flag set
		     fails, try	again using the	chain validation model.

       sshcontrol
	      This file	is used	when support for the secure shell agent	protocol has
	      been enabled (see: [option --enable-ssh-support]). Only keys present in
	      this file	are used in the	SSH protocol.  You should backup this file.

	      The ssh-add tool may be used to add new entries to this file;
	      you may also add them manually.  Comment lines, indicated	by a leading
	      hash mark, as well as empty lines	are ignored.  An entry starts with
	      optional whitespace, followed by the keygrip of the key given as 40 hex
	      digits, optionally followed by the caching TTL in	seconds	and another
	      optional field for arbitrary flags.  A non-zero TTL overrides the	global
	      default as set by	--default-cache-ttl-ssh.

	      The only flag support is confirm.	 If this flag is found for a
	      key, each	use of the key will pop	up a pinentry to confirm the use of
	      that key.	 The flag is automatically set if a new	key was	loaded into
	      gpg-agent	using the option -c of the ssh-add
	      command.

	      The keygrip may be prefixed with a ! to disable an entry entry.

	      The following example lists exactly one key.  Note that keys available
	      through a	OpenPGP	smartcard in the active	smartcard reader are
	      implicitly added to this list; i.e. there	is no need to list them.

		.RS 2
		# Key added on:	2011-07-20 20:38:46
		# Fingerprint:	5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81
		34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm
		.fi

       private-keys-v1.d/

		This is	the directory where gpg-agent stores the private keys.	Each
		key is stored in a file	with the name made up of the keygrip and the
		suffix `key'.  You should backup all files in this directory
		and take great care to keep this backup	closed away.

	      Note that	on larger installations, it is useful to put predefined
	      files into the directory `/etc/skel/.gnupg/' so that newly created
	      users start up with a working configuration.  For	existing users the
	      a	small helper script is provided	to create these	files (see: [addgnupghome]).

SIGNALS
       A  running  gpg-agent may be controlled by signals, i.e.	using the kill
       command to send a signal	to the process.

       Here is a list of supported signals:

       SIGHUP This signal flushes all cached passphrases and  if  the  program
	      has  been	 started  with a configuration file, the configuration
	      file is read again.  Only	certain	options	 are  honored:	quiet,
	      verbose,	debug,	debug-all, debug-level,	no-grab, pinentry-pro-
	      gram, default-cache-ttl,	max-cache-ttl,	ignore-cache-for-sign-
	      ing, no-allow-external-cache, allow-mark-trusted,	disable-scdae-
	      mon, and	disable-check-own-socket.   scdaemon-program  is  also
	      supported	but due	to the current implementation, which calls the
	      scdaemon only once, it is	not of much use	 unless	 you  manually
	      kill the scdaemon.

       SIGTERM
	      Shuts  down the process but waits	until all current requests are
	      fulfilled.  If the process has received 3	of these  signals  and
	      requests are still pending, a shutdown is	forced.

       SIGINT Shuts down the process immediately.

       SIGUSR1
	      Dump internal information	to the log file.

       SIGUSR2
	      This signal is used for internal purposes.

SEE ALSO
       gpg2(1),	gpgsm(1), gpg-connect-agent(1),	scdaemon(1)

       The full	documentation for this tool is maintained as a Texinfo manual.
       If GnuPG	and the	info program are properly installed at your site,  the
       command

	 info gnupg

       should  give  you access	to the complete	manual including a menu	struc-
       ture and	an index.

GnuPG 2.0.30			  2017-07-08			  GPG-AGENT(1)

NAME | SYNOPSIS | DESCRIPTION | COMMANDS | OPTIONS | EXAMPLES | FILES | SIGNALS | SEE ALSO

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