Provided by: scdaemon_2.2.4-1ubuntu1.6_amd64 
NAME
scdaemon - Smartcard daemon for the GnuPG system
SYNOPSIS
scdaemon [--homedir dir] [--options file] [options] --server
scdaemon [--homedir dir] [--options file] [options] --daemon [command_line]
DESCRIPTION
The scdaemon is a daemon to manage smartcards. It is usually invoked by gpg-agent and in general not
used directly.
COMMANDS
Commands are not distinguished from options except for the fact that only one command is allowed.
--version
Print the program version and licensing information. Note that you cannot abbreviate this
command.
--help, -h
Print a usage message summarizing the most useful command-line options. Note that you cannot
abbreviate this command.
--dump-options
Print a list of all available options and commands. Note that you cannot abbreviate this command.
--server
Run in server mode and wait for commands on the stdin. The default mode is to create a socket and
listen for commands there.
--multi-server
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.
--daemon
Run the program in the background. This option is required to prevent it from being accidentally
running in the background.
OPTIONS
--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 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.
-v
--verbose
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.
advanced
More verbose debug messages. A value between 3 and 5 may be used instead of the keyword.
expert Even more detailed messages. A value between 6 and 8 may be used instead of the keyword.
guru All of the debug messages you can get. A value greater than 8 may be used instead of the
keyword. The creation of hash tracing files is only enabled if the keyword is used.
How these messages are mapped to the actual debugging flags is not specified and may change with newer
releases of this program. They are however carefully selected to best aid in debugging.
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 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.
--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-ccid-driver
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.
--debug-disable-ticker
This option disables all ticker functions like checking for card insertions.
--debug-allow-core-dump
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.
--debug-log-tid
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.
--no-detach
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 ‘libpcsclite.so’. Instead of
using this option you might also want to install a symbolic link to the default file name (e.g.
from ‘libpcsclite.so.1’).
--ctapi-driver library
Use library to access the smartcard reader. The current default is ‘libtowitoko.so’. Note that
the use of this interface is deprecated; it may be removed in future releases.
--disable-ccid
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 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.
--enable-pinpad-varlen
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.
--disable-pinpad
Even if a card reader features a pinpad, do not try to use it.
--deny-admin
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 default.
All the long options may also be given in the configuration file after stripping off the two leading
dashes.
CARD APPLICATIONS
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
(http://g10code.com/docs/openpgp-card-1.0.pdf) and
(http://g10code.com/docs/openpgp-card-2.0.pdf).
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 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 (http://www.smartcard-
hsm.com, SmartCard-HSM).
To generate keys and store certifiates you may use (https://github.com/OpenSC/OpenSC/wiki/SmartCardHSM,
OpenSC) or the tools from (http://www.openscdp.org, 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.
EXAMPLES
$ scdaemon --server -v
FILES
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]).
scdaemon.conf
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]).
scd-event
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
reader_n.status
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’.
SEE ALSO
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.