SCDAEMON(1) GNU Privacy Guard 2.2 SCDAEMON(1)
NAME
scdaemon - Smartcard daemon for the GnuPG system
SYNOPSIS
scdaemon [--homedir dir] [--options file] [options] --server
scdaemon [--homedir dir] [--options file] [options] --daemon [com-
mand_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 de-
fault 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 di-
rectly 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 en-
try 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 con-
sidered, 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 be-
low 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 smart-
cards. 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 use-
ful 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 see-
ing what the agent actually does. Use ‘socket://’ to log to
socket.
--pcsc-shared
Use shared mode to access the card via PC/SC. This is a some-
what dangerous option because Scdaemon assumes exclusivbe access
to teh card and for example caches certain information from the
card. Use this option only if you know what you are doing.
--pcsc-driver library
Use library to access the smartcard reader. The current default
on Unix is ‘libpcsclite.so’ and on Windows ‘winscard.dll’. In-
stead of using this option you might also want to install a sym-
bolic link to the default file name (e.g. from ‘libpc-
sclite.so.1’). A Unicode file name may not be used on Windows.
--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 in-
ternal CCID driver can handle the reader. Note, that CCID sup-
port 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 termi-
nal. 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 com-
mand:
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 cer-
tain 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 pow-
ered 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 vari-
able 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 acciden-
tal 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 re-
quired to use such admin commands. This option has no more ef-
fect 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 sup-
ported.
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 Ger-
many. 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 sig-
nature 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 Geld-
karte. 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 certificates 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 sc-
daemons'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: [op-
tion --options]).
scd-event
If this file is present and executable, it will be called on ev-
ery 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 struc-
ture and an index.
GnuPG 2.2.40 2022-10-07 SCDAEMON(1)
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