man > GPG-AGENT(1)

GPG-AGENT(1)                            GNU Privacy Guard 2.4                           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 [command_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  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:

         GPG_TTY=$(tty)
         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. ‘/usr/bin/pinentry’).




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


       --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 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 seconds.


       --supervised
              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 option is
              deprecated and not supported on Windows.

              If in ‘common.conf’ the option no-autostart is set, any start  attempts  will  be  ig‐
              nored.

              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 vari‐
              able LISTEN_FDNAMES (see sd_listen_fds(3) on some Linux distributions for more  infor‐
              mation on this convention).

OPTIONS
       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 direc‐
              tory 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  HKCU\Soft‐
              ware\GNU\GnuPG:HomeDir.

              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 direc‐
              tory are ignored.



       -v
       --verbose
              Outputs additional information while running.  You can increase the verbosity by  giv‐
              ing several verbose commands to gpg-agent, 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  key‐
                     word.

              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  in‐
                     stead  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 de‐
       bugging.


       --debug flags
              Set debug flags.  All flags are or-ed and flags may be given in C syntax (e.g. 0x0042)
              or as a comma separated list of flag names.  To get a list of all supported flags  the
              single  word  "help" can be used. This option is only useful for debugging and the be‐
              havior may change at any time without notice.


       --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.


       --debug-quick-random
              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 /dev/urandom’.


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


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


       --steal-socket
              In  --daemon  mode,  gpg-agent detects an already running gpg-agent and does not allow
              one to start a new instance. This option can be used to override this check:  the  new
              gpg-agent  process  will  try  to take over the communication sockets from the already
              running process and start anyway.  This option should in general not be used.



       -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 correct in almost all cases.



       --grab
       --no-grab
              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 ac‐
              tually 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\Soft‐
              ware\GNU\GnuPG:DefaultLogFile, if set, is used to specify the logging output.




       --no-allow-mark-trusted
              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.




       --no-user-trustlist
              Entirely   ignore  the  user  trust  list  and  consider  only  the  global  trustlist
              (‘/etc/gnupg/trustlist.txt’).  This implies the [option --no-allow-mark-trusted].


       --sys-trustlist-name file
              Changes the default name for the global trustlist from "trustlist.txt"  to  file.   If
              file  does  not contain any slashes and does not start with "~/" it is searched in the
              system configuration directory (‘/etc/gnupg’).



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



       --no-allow-loopback-pinentry

       --allow-loopback-pinentry
              Disallow or allow clients to use the loopback pinentry features; see the option pinen‐
              try-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.


       --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 employs an additional external cache to imple‐
              ment  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.


       --allow-emacs-pinentry
              Tell Pinentry to allow features to divert the passphrase entry to a running Emacs  in‐
              stance.  How this is exactly handled depends on the version of the used Pinentry.


       --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 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.  Note that a cached passphrase may not be evicted immedi‐
              ately from memory if no client requests a cache operation.  This is due to an internal
              housekeeping function which is only run every few seconds.


       --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 en‐
              try  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-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-sym-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.  If file does
              not contain any slashes and does not start with "~/" it is searched in the system con‐
              figuration directory (‘/etc/gnupg’).  The default is not to use any pattern file.  The
              second version of this option is only used when creating a new symmetric key to  allow
              the use of different patterns for such passphrases.

              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-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 de‐
              fault 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 request.


       --pinentry-formatted-passphrase
              This option asks the Pinentry to enable passphrase formatting when asking the user for
              a new passphrase and masking of the passphrase is turned off.

              If  passphrase  formatting  is  enabled,  then  all  non-breaking space characters are
              stripped from the entered passphrase.  Passphrase formatting is mostly useful in  com‐
              bination  with passphrases generated with the GENPIN feature of some Pinentries.  Note
              that such a generated passphrase, if not modified by the user,  skips  all  passphrase
              constraints  checking  because  such  constraints  would actually weaken the generated
              passphrase.


       --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 time.



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


       --disable-scdaemon
              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.


       --disable-check-own-socket
              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 ter‐
              minate itself.  This option may be used to disable this self-test for  debugging  pur‐
              poses.


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


       --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  re‐
              spectively.   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  con‐
              nect  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  ma‐
              chine.


       --enable-extended-key-format
       --disable-extended-key-format
              These  options  are  obsolete and have no effect.  The extended key format is used for
              years now and has been supported since 2.1.12.  Existing keys in the  old  format  are
              migrated to the new format as soon as they are touched.




       --enable-ssh-support
       --enable-win32-openssh-support
       --enable-putty-support

              On  Unix  platforms  the  OpenSSH Agent protocol is always enabled, but gpg-agent will
              only set the SSH_AUTH_SOCK variable if the option enable-ssh-support is  given.   Some
              Linux  distributions  use  the  presence of this option to decide whether the old ssh-
              agent shall be started.

              On Windows support for the native ssh implementation must be enabled using the the op‐
              tion enable-win32-openssh-support.  For using gpg-agent as a replacement  for  PuTTY's
              Pageant, the option enable-putty-support must be enabled.

              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  or  via  Named
              Pipes)  or  the protocol used by PuTTY.  Consequently, this allows one to use the gpg-
              agent as a drop-in replacement for the 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 fol‐
              lowing 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  authentica‐
       tion.  To fix this you may start gpg-agent if needed using this simple command:

         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.


       The order in which keys are presented to ssh are:


              Negative Use-for-ssh values
                           If a key file has the attribute "Use-for-ssh" and its value is
                           negative, these keys are presented first to ssh.  The negative
                           values are capped at -999 with -999 being lower ranked than -1.
                           These values can be used to prefer on-disk keys over keys taken
                           from active cards.


              Active cards
                           Active cards (inserted into a card reader or plugged in tokens)
                           are always tried; they are ordered by their serial numbers.


              Keys listed in the sshcontrol file
                           Non-disabled keys from the sshcontrol file are presented in the
                           order they appear in this file.  Note that the sshcontrol file
                           is deprecated.


              Positive Use-for-ssh values
                           If a key file has the attribute "Use-for-ssh" and its value is
                           "yes", "true", or any positive number the key is presented in
                           the order of their values.  "yes" and "true" have a value of 1;
                           other values are capped at 99999.


       Editing  the  "Use-for-ssh"  values can be done with an editor or using gpg-connect-agent and
       "KEYATTR" (Remember to append a colon to the key; i.e. use "Use-for-ssh:").




       --ssh-fingerprint-digest

              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 pre‐
              fixes 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-calibration milliseconds
              Change the default calibration time to milliseconds.  The given value is capped at  60
              seconds;  a value of 0 resets to the compiled-in default.  This option is re-read on a
              SIGHUP (or gpgconf --reload gpg-agent) and the S2K count is then re-calibrated.


       --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 by default 100ms to mangle a given passphrase.  See  also  --s2k-
              calibration.

              To view the actually used iteration count and the milliseconds required for an S2K op‐
              eration 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



EXAMPLES
       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)"
         fi




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 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.


       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
                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
                .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 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;
       the [option --no-user-trustlist] enforces the use of only
       this global list.

       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.


              qual   The CA is allowed to issue certificates for qualified signatures.
                     This flag has an effect only if used in the global list.  This is now
                     the preferred way to mark such CA; the old way of having a separate
                     file ‘qualified.txt’ is still supported.


              de-vs  The CA is part of an approved PKI for the German classification level
                     VS-NfD.  It is only valid in the global trustlist.  As of now this is
                     used only for documentation purpose.




       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.

              This file is deprecated in favor of the "Use-for-ssh" attribute in the
              key files.

              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.

              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


       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:  [ad‐
       dgnupghome]).




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



       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
       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.

GnuPG 2.4.4                                  2024-01-25                                 GPG-AGENT(1)
GPG-AGENT(1)
NAME SYNOPSIS DESCRIPTION COMMANDS
--version --help -h Print a usage message summarizing the most useful command-line options. Note that you --dump-options --server --supervised
OPTIONS
-v --verbose -q --quiet --batch --debug-all --debug-quick-random --debug-pinentry --no-detach --steal-socket -s --sh -c --grab --no-grab --no-allow-mark-trusted --no-user-trustlist --allow-preset-passphrase --no-allow-loopback-pinentry --allow-loopback-pinentry --no-allow-external-cache --allow-emacs-pinentry --ignore-cache-for-signing --enforce-passphrase-constraints --enable-passphrase-history --pinentry-formatted-passphrase --disable-scdaemon --disable-check-own-socket --use-standard-socket --no-use-standard-socket --use-standard-socket-p --keep-tty --keep-display --enable-extended-key-format --disable-extended-key-format --enable-ssh-support --enable-win32-openssh-support --enable-putty-support --ssh-fingerprint-digest
EXAMPLES FILES
gpg-agent.conf trustlist.txt sshcontrol private-keys-v1.d/
SIGNALS SEE ALSO

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