Provided by: gpg-agent_2.2.4-1ubuntu1.6_amd64 bug


       gpg-agent - Secret key management for GnuPG


       gpg-agent [--homedir dir] [--options file] [options]
       gpg-agent [--homedir dir] [--options file] [options] --server
       gpg-agent [--homedir dir] [--options file] [options] --daemon [command_line]


       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 agent is automatically started on demand by gpg, gpgsm, gpgconf, or gpg-connect-agent.
       Thus there is no reason to start it manually.  In case you want to use the included Secure
       Shell Agent you may start the agent using:

         gpg-connect-agent /bye

       If you want to manually terminate the currently-running agent, you can safely do so with:

         gpgconf --kill gpg-agent

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

         export GPG_TTY

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

       Please make sure that a proper pinentry program  has  been  installed  under  the  default
       filename  (which  is  system  dependent) 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.


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

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

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

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

              Run in server mode and wait for commands on the stdin.   The  default  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.

              As an alternative you may create 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; after you exit  from  this  shell,  gpg-agent  terminates  within  a  few

              Run in the foreground, sending logs by default to stderr, and listening on provided
              file descriptors, which must already be bound to listening sockets.   This  command
              is  useful when running under systemd or other similar process supervision schemes.
              This option is not supported on Windows.

              In --supervised mode, different  file  descriptors  can  be  provided  for  use  as
              different  socket  types  (e.g.  ssh,  extra) as long as they are identified in the
              environment  variable  LISTEN_FDNAMES   (see   sd_listen_fds(3)   on   some   Linux
              distributions for more information on this convention).


       Options  may  either  be  used on the command line or, after stripping off the two leading
       dashes, in the configuration file.

       --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.  This  option  is
              ignored if used in an options file.

       --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  Windows   systems)   by   means   of   the   Registry   entry

              On  Windows  systems it is possible to install GnuPG as a portable application.  In
              this case only this command line option is considered, all other ways to set a home
              directory are ignored.

              To  install  GnuPG  as  a  portable application under Windows, create an empty file
              named ‘gpgconf.ctl’ in the same directory as the tool ‘gpgconf.exe’.  The  root  of
              the  installation  is  then that directory; or, if ‘gpgconf.exe’ has been installed
              directly below a directory named ‘bin’, its parent directory.   You  also  need  to
              make  sure  that  the following directories exist and are writable: ‘ROOT/home’ for
              the GnuPG home and ‘ROOT/var/cache/gnupg’ for internal cache files.


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


              Try to be as quiet as possible.

              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

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

                     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 behavior 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

              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.

              This option inhibits the use of the very secure random quality  level  (Libgcrypt’s
              GCRY_VERY_STRONG_RANDOM)  and degrades all request down to standard random quality.
              It is only used for testing and should not be used for any production quality keys.
              This option is only effective when given on the command line.

              On  GNU/Linux, another way to quickly generate insecure keys is to use rngd to fill
              the kernel's entropy pool with  lower  quality  random  data.   rngd  is  typically
              provided  by  the  rng-tools  package.   It can be run as follows: 'sudo rngd -f -r

              This option enables extra debug information pertaining to the Pinentry.  As of  now
              it is only useful when used along with --debug 1024.

              Don't detach the process from the console.  This is mainly useful for debugging.

       --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 correct in almost all cases.

              Tell the pinentry to grab the keyboard and mouse.  This option should be used on X-
              Servers to avoid X-sniffing attacks. Any use of the option --grab overrides an used
              option --no-grab.  The default is --no-grab.

       --log-file file
              Append  all  logging output to file.  This is very helpful in seeing what the agent
              actually does. Use ‘socket://’ to log to socket.  If neither a log file nor  a  log
              file   descriptor   has  been  set  on  a  Windows  platform,  the  Registry  entry
              HKCU\Software\GNU\GnuPG:DefaultLogFile, if set, is  used  to  specify  the  logging

              Do   not   allow  clients  to  mark  keys  as  trusted,  i.e.  put  them  into  the
              ‘trustlist.txt’ file.  This makes it harder for users to inadvertently accept Root-
              CA keys.

              This  option  allows the use of gpg-preset-passphrase to seed the internal cache of
              gpg-agent with passphrases.


              Disallow or allow clients to use the loopback pinentry  features;  see  the  option
              pinentry-mode for details.  Allow is the default.

              The  --force  option  of  the  Assuan command DELETE_KEY is also controlled by this
              option: The option is ignored if a loopback pinentry is disallowed.

              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 employs 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.

              Tell  Pinentry  to allow features to divert the passphrase entry to a running Emacs
              instance.  How this is exactly handled depends on the version of the used Pinentry.

              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 behavior
              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.
              Each time a cache entry is accessed, the entry's timer is reset.  To set an entry's
              maximum lifetime, use max-cache-ttl.

       --default-cache-ttl-ssh n
              Set the time a cache entry used for SSH keys is valid to n seconds.  The default is
              1800 seconds.  Each time a cache entry is accessed, the entry's timer is reset.  To
              set an entry's maximum lifetime, use max-cache-ttl-ssh.

       --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 accessed 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-preset-passphrase.  The default is 2 hours (7200 seconds).

              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 warning 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

       --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.

              This option does nothing yet.

       --pinentry-invisible-char char
              This option asks the Pinentry to use char for displaying hidden  characters.   char
              must be one character UTF-8 string.  A Pinentry may or may not honor this request.

       --pinentry-timeout n
              This  option  asks the Pinentry to timeout after n seconds with no user input.  The
              default value of 0 does not ask the pinentry to timeout, however a Pinentry may use
              its  own  default timeout value in this case.  A Pinentry may or may not honor this

       --pinentry-program filename
              Use program filename as the PIN entry.   The  default  is  installation  dependent.
              With  the  default configuration the name of the default pinentry is ‘pinentry’; if
              that file does not exist but a ‘pinentry-basic’ exist the latter is used.

              On a Windows platform the default is to use the first existing  program  from  this
              list: ‘bin\pinentry.exe’, ‘..\Gpg4win\bin\pinentry.exe’, ‘..\Gpg4win\pinentry.exe’,
              ‘..\GNU\GnuPG\pinentry.exe’,  ‘..\GNU\bin\pinentry.exe’,   ‘bin\pinentry-basic.exe’
              where the file names are relative to the GnuPG installation directory.

       --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

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

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

              gpg-agent  employs  a  periodic  self-test to detect a stolen socket.  This usually
              means a second instance of gpg-agent has taken over the socket and  gpg-agent  will
              then  terminate  itself.   This  option  may  be used to disable this self-test for
              debugging purposes.

              Since GnuPG 2.1 the standard socket is always used.  These  options  have  no  more
              effect.   The  command  gpg-agent  --use-standard-socket-p  will thus always return

       --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.

              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.

       --listen-backlog n
              Set the size of the queue for pending connections.  The default is 64.

       --extra-socket name
              The extra socket is created by default, you may use this option to change the  name
              of the socket.  To disable the creation of the socket use ``none'' or ``/dev/null''
              for name.

              Also listen on native gpg-agent connections on the given socket.  The intended  use
              for  this  extra  socket  is to setup a Unix domain socket forwarding from a remote
              machine to this socket on the local machine.  A gpg running on the  remote  machine
              may  then  connect  to  the local gpg-agent and use its private keys.  This enables
              decrypting or signing data on a remote machine without exposing the private keys to
              the remote machine.

              This  option  creates  keys  in  the  extended  private  key  format.  Changing the
              passphrase of a key will also convert the key  to  that  new  format.   Using  this
              option makes the private keys unreadable for gpg-agent versions before 2.1.12.  The
              advantage of the extended private key format is that it is text based and can carry
              additional meta data.  Note that this option also changes the key protection format
              to use OCB mode.


              The OpenSSH Agent protocol is always enabled,  but  gpg-agent  will  only  set  the
              SSH_AUTH_SOCK variable if this flag is given.

              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 possible 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 necessary for decrypting the stored key.  Since
              the  ssh-agent protocol 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 able to  use  gpg-agent
       for  authentication.   To  fix  this  you  may start gpg-agent if needed using this simple

         gpg-connect-agent /bye

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

       The --enable-putty-support is only available under Windows and allows the use of gpg-agent
       with  the  ssh implementation putty.  This is similar to the regular ssh-agent support but
       makes use of Windows message queue as required by putty.


              Select the digest algorithm used to compute ssh fingerprints that are  communicated
              to  the user, e.g. in pinentry dialogs.  OpenSSH has transitioned from using MD5 to
              the more secure SHA256.

       --auto-expand-secmem n
              Allow Libgcrypt to expand its secure memory area as required.  The optional value n
              is  a  non-negative  integer  with  a  suggested size in bytes of each additionally
              allocated secure memory area.  The value is rounded up to the next 32 KiB; usual  C
              style  prefixes  are  allowed.   For an heavy loaded gpg-agent with many concurrent
              connection this option avoids sign or decrypt errors due to out  of  secure  memory
              error returns.

       --s2k-count n
              Specify  the  iteration  count  used to protect the passphrase.  This option can be
              used to override  the  auto-calibration  done  by  default.   The  auto-calibration
              computes a count which requires 100ms to mangle a given passphrase.

              To  view the actually used iteration count and the milliseconds required for an S2K
              operation use:

         gpg-connect-agent 'GETINFO s2k_count' /bye
         gpg-connect-agent 'GETINFO s2k_time' /bye

       To view the auto-calibrated count use:

         gpg-connect-agent 'GETINFO s2k_count_cal' /bye


       It is important to set the environment variable GPG_TTY in your login shell,  for  example
       in the ‘~/.bashrc’ init script:

           export GPG_TTY=$(tty)

       If you enabled the Ssh Agent Support, you also need to tell ssh about it by adding this to
       your init script:

         unset SSH_AGENT_PID
         if [ "${gnupg_SSH_AUTH_SOCK_by:-0}" -ne $$ ]; then
           export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"


       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]).

                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 abbreviated.
                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.

                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
                enables cutting and pasting 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

       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 disallowing interactive
       updates of this file by using the [option --no-allow-mark-trusted].
       It might even be 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

              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.

              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

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

                # 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


                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:


       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, debug-pinentry, no-
              grab, pinentry-program, pinentry-invisible-char, default-cache-ttl,  max-cache-ttl,
              ignore-cache-for-signing, s2k-count, no-allow-external-cache, allow-emacs-pinentry,
              no-allow-mark-trusted, disable-scdaemon, 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.

              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.

              Dump internal information to the log file.

              This signal is used for internal purposes.


       gpg(1), gpgsm(1), gpgconf(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 structure and an index.