Provided by: scdaemon_2.2.4-1ubuntu1.6_amd64 bug


       scdaemon - Smartcard daemon for the GnuPG system


       scdaemon [--homedir dir] [--options file] [options] --server
       scdaemon [--homedir dir] [--options file] [options] --daemon [command_line]


       The  scdaemon is a daemon to manage smartcards.  It is usually invoked by gpg-agent and in
       general not used directly.


       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.

       --help, -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.

              Run  in  server mode and wait for commands on the stdin as well as on an additional
              Unix Domain socket.  The server command GETINFO may be used to get the name of that
              extra socket.

              Run  the  program  in  the  background.  This option is required to prevent it from
              being accidentally running in the background.


       --options file
              Reads configuration from file instead of from the  default  per-user  configuration
              file.   The default configuration file is named ‘scdaemon.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   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 gpgsm, such as '-vv'.

       --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.

              All  debugging  options  are  subject  to change and thus should not be used by any
              application program.  As the name says, they are only  used  as  helpers  to  debug

       --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)  command I/O

              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.  See also option --debug-assuan-log-cats.

              11 (2048)
                     trace APDU I/O to the card.  This may reveal sensitive data.

              12 (4096)
                     trace some card reader related function calls.

              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.

              Enable debug output from the included  CCID  driver  for  smartcards.   Using  this
              option  twice  will  also  enable some tracing of the T=1 protocol.  Note that this
              option may reveal sensitive data.

              This option disables all ticker functions like checking for card insertions.

              For security reasons we won't create a core dump  when  the  process  aborts.   For
              debugging  purposes it is sometimes better to allow core dump.  This option enables
              it and also changes the working directory to ‘/tmp’ when running in --server mode.

              This option appends a thread ID to the PID in the log output.

       --debug-assuan-log-cats cats
              Changes the active Libassuan logging categories to cats.  The value for cats is  an
              unsigned  integer  given  in  usual  C-Syntax.   A value of 0 switches to a default
              category.  If this option is not used the categories are taken from the environment
              variable  ASSUAN_DEBUG.   Note  that  this  option has only an effect if the Assuan
              debug flag has also been with the option --debug.  For a list of categories see the
              Libassuan manual.

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

       --listen-backlog n
              Set the size of the queue for pending connections.  The default is 64.  This option
              has an effect only if --multi-server is also used.

       --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.

       --pcsc-driver library
              Use   library   to   access   the   smartcard   reader.   The  current  default  is
              ‘’.  Instead of using this option you might also want  to  install  a
              symbolic link to the default file name (e.g. from ‘’).

       --ctapi-driver library
              Use   library   to   access   the   smartcard   reader.   The  current  default  is
              ‘’.  Note that the use of this interface is  deprecated;  it  may  be
              removed in future releases.

              Disable  the  integrated  support  for CCID compliant readers.  This allows falling
              back to one of the other drivers even if the internal CCID driver  can  handle  the
              reader.  Note, that CCID support is only available if libusb was available at build

       --reader-port number_or_string
              This option may be used to specify the port of the card terminal.   A  value  of  0
              refers to the first serial device; add 32768 to access USB devices.  The default is
              32768 (first USB device).  PC/SC or CCID readers might need a string here; run  the
              program  in  verbose  mode to get a list of available readers.  The default is then
              the first reader found.

              To get a list of available CCID readers you may use this command:
           echo scd getinfo reader_list \
             | gpg-connect-agent --decode | awk '/^D/ {print $2}'

       --card-timeout n
              If n is not 0 and no client is actively using the card, the card  will  be  powered
              down after n seconds.  Powering down the card avoids a potential risk of damaging a
              card when used with certain cheap readers.  This also allows applications that  are
              not aware of Scdaemon to access the card.  The disadvantage of using a card timeout
              is that accessing the card takes longer and that the user needs to  enter  the  PIN
              again after the next power up.

              Note that with the current version of Scdaemon the card is powered down immediately
              at the next timer tick for any value of n other than 0.

              Please specify this option when the card reader supports variable length input  for
              pinpad  (default  is  no).  For known readers (listed in ccid-driver.c and apdu.c),
              this option is not needed.  Note that if your card reader doesn't supports variable
              length  input  but  you  want to use it, you need to specify your pinpad request on
              your card.

              Even if a card reader features a pinpad, do not try to use it.

              This option disables the use of admin class commands for  card  applications  where
              this  is  supported.   Currently we support it for the OpenPGP card. This option is
              useful to inhibit accidental access to admin class command which  could  ultimately
              lock  the  card  through  wrong  PIN  numbers.  Note that GnuPG versions older than
              2.0.11 featured an --allow-admin option  which  was  required  to  use  such  admin
              commands.  This option has no more effect today because the default is now to allow
              admin commands.

       --disable-application name
              This option disables the use of the card application named name.   This  is  mainly
              useful  for  debugging  or  if  a application with lower priority should be used by

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


       scdaemon supports the card applications as described below.

   The OpenPGP card application ``openpgp''

       This  application  is  currently  only  used  by gpg but may in future also be useful with
       gpgsm.  Version 1 and version 2 of the card is supported.

       The specifications for these cards are available at
       ( and

   The Telesec NetKey card ``nks''

       This is the main application of the Telesec cards  as  available  in  Germany.   It  is  a
       superset of the German DINSIG card.  The card is used by gpgsm.

   The DINSIG card application ``dinsig''

       This  is  an  application  as described in the German draft standard DIN V 66291-1.  It is
       intended to be used by cards supporting the German signature law and its bylaws (SigG  and

   The PKCS#15 card application ``p15''

       This is common framework for smart card applications.  It is used by gpgsm.

   The Geldkarte card application ``geldkarte''

       This  is a simple application to display information of a German Geldkarte.  The Geldkarte
       is a small amount debit card application which comes with almost all German banking cards.

   The SmartCard-HSM card application ``sc-hsm''

       This  application  adds  read-only  support  for  keys  and  certificates  stored   on   a
       (, SmartCard-HSM).

       To      generate      keys      and      store      certifiates      you      may      use
       (,   OpenSC)   or   the    tools    from
       (, OpenSCDP).

       The SmartCard-HSM cards requires a card reader that supports Extended Length APDUs.

   The Undefined card application ``undefined''

       This  is  a  stub  application  to  allow the use of the APDU command even if no supported
       application is found on the card.  This application is not used automatically but must  be
       explicitly requested using the SERIALNO command.


         $ scdaemon --server -v


       There  are  a few configuration files to control certain aspects of scdaemons's operation.
       Unless noted, they are expected in the current home directory (see: [option --homedir]).

              This is the standard configuration file  read  by  scdaemon  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 default name may be  changed  on  the  command
              line (see: [option --options]).

              If  this  file  is present and executable, it will be called on every card reader's
              status change.  An example of this script is provided with the distribution

              This file is created by scdaemon to let other applications now about reader  status
              changes.  Its use is now deprecated in favor of ‘scd-event’.


       gpg-agent(1), gpgsm(1), gpg2(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.