scdaemon - Smartcard daemon for the GnuPG system


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


   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 allowed.

          Print the program version and licensing information.   Not  that
          you can abbreviate this command.

   --help, -h
          Print  a  usage message summarizing the most useful command-line
          options.  Not that you can abbreviate this command.

          Print a list of all available options and  commands.   Not  that
          you can abbreviate this command.

          Run  in server mode and wait for commands on the stdin.  This is
          default mode is to create  a  socket  and  listen  for  commands

          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 HKCU\Software\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 directory are ignored.

          To install GnuPG as a portable application under Windows, create
          an  empty  file  name 'gpgconf.ctl' in the same directory as the
          tool 'gpgconf.exe'.  The root of the installation is  than  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 keyword.

          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

   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 problems.

   --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)  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-

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

          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

          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 options 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 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.

   --log-file file
          Append  all  logging  output  to  file.  This is very helpful in
          seeing what the agent actually does.

   --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 time.

   --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
       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

          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  commands  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 command
          which was required to use such admin commands.  This option  has
          no  more  effect today because the default is now to allow admin

   --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 default.

   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

   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 SigV).

   The PKCS#15 card application ``p15''

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

   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


     $ 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
          veyer card reader's status changed. An example of this script is
          provided with the distribution

          This  file  is  created by sdaemon 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

     info gnupg

   should  give  you  access  to  the  complete  manual  including  a menu
   structure and an index.


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