gnupg/doc/scdaemon.texi

@c Copyright (C) 2002 Free Software Foundation, Inc.
@c This is part of the GnuPG manual.
@c For copying conditions, see the file gnupg.texi.

@node Invoking SCDAEMON
@chapter Invoking the SCDAEMON
@cindex SCDAEMON command options
@cindex command options
@cindex options, SCDAEMON command

@c man begin DESCRIPTION

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

@c man end

@xref{Option Index}, for an index to GPG-AGENTS's commands and options.

@menu
* Scdaemon Commands::      List of all commands.
* Scdaemon Options::       List of all options.
* Card applications::      Description of card applications.
* Scdaemon Examples::      Some usage examples.
* Scdaemon Protocol::      The protocol the daemon uses.
@end menu

@c man begin COMMANDS

@node Scdaemon Commands
@section Commands

Commands are not distinguished from options execpt for the fact that
only one one command is allowed.

@table @gnupgtabopt
@item --version
@opindex version
Print the program version and licensing information.  Not that you can
abbreviate this command.

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

@item --dump-options
@opindex dump-options
Print a list of all available options and commands.  Not that you can
abbreviate this command.

@item --server
@opindex server
Run in server mode and wait for commands on the @code{stdin}.  This is
default mode is to create a socket and listen for commands there.

@item --daemon
@opindex daemon
Run the program in the background.  This option is required to prevent
it from being accidently running in the background.

@item --print-atr
@opindex print-atr
This is mainly a debugging command, used to print the ATR
(Answer-To-Reset) of a card and exit immediately. 

@end table


@c man begin OPTIONS

@node Scdaemon Options
@section Option Summary

@table @gnupgtabopt

@item --options @var{file}
@opindex options
Reads configuration from @var{file} instead of from the default
per-user configuration file.  The default configuration file is named
@file{scdaemon.conf} and expected in the @file{.gnupg} directory directly
below the home directory of the user.

@item --homedir @var{dir}
@opindex homedir
Set the name of the home directory to @var{dir}. If his option is not
used, the home directory defaults to @file{~/.gnupg}.  It is only
recognized when given on the command line.  It also overrides any home
directory stated through the environment variable @env{GNUPGHOME} or
(on W32 systems) by means on the Registry entry
@var{HKCU\Software\GNU\GnuPG:HomeDir}.

@item -v
@item --verbose
@opindex v
@opindex verbose
Outputs additional information while running.
You can increase the verbosity by giving several
verbose commands to @command{gpgsm}, such as @samp{-vv}.

@item --debug-level @var{level}
@opindex debug-level
Select the debug level for investigating problems. @var{level} may be
one of:

   @table @code
   @item none
   no debugging at all.
   @item basic  
   some basic debug messages
   @item advanced
   more verbose debug messages
   @item expert
   even more detailed messages
   @item guru
   all of the debug messages you can get
   @end table

How these messages are mapped to the actual debugging flags is not
specified and may change with newer releaes of this program. They are
however carefully selected to best aid in debugging.

@item --debug @var{flags}
@opindex debug
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:

   @table @code
   @item 0  (1)
   X.509 or OpenPGP protocol related data
   @item 1  (2)  
   values of big number integers 
   @item 2  (4)
   low level crypto operations
   @item 5  (32)
   memory allocation
   @item 6  (64)
   caching
   @item 7  (128)
   show memory statistics.
   @item 9  (512)
   write hashed data to files named @code{dbgmd-000*}
   @item 10 (1024)
   trace Assuan protocol
   @item 12 (4096)
   bypass all certificate validation
   @end table

@item --debug-all
@opindex debug-all
Same as @code{--debug=0xffffffff}

@item --debug-wait @var{n}
@opindex debug-wait
When running in server mode, wait @var{n} seconds before entering the
actual processing loop and print the pid.  This gives time to attach a
debugger.

@item --debug-sc @var{n}
@opindex debug-sc
Set the debug level of the OpenSC library to @var{n}.

@item --no-detach
@opindex no-detach
Don't detach the process from the console.  This is manly usefule for
debugging.

@item --log-file @var{file}
@opindex log-file
Append all logging output to @var{file}.  This is very helpful in
seeing what the agent actually does.

@item --reader-port @var{number}
When the program has been build without OpenSC support, this option must
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).

@item --ctapi-driver @var{library}
Use @var{library} to access the smartcard reader.  The current default
is @code{libtowitoko.so}.  Note that the use of this interface is
deprecated; it may be removed in future releases.


@item --allow-admin
@itemx --deny-admin
@opindex allow-admin
@opindex deny-admin
This enables the use of Admin class commands for card applications
where this is supported.  Currently we support it for the OpenPGP
card.  Deny is the default.  This commands is useful to inhibit
accidental access to admin class command which could ultimately lock
the card through worng PIN numbers.

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

@end table

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


@c man begin CARD APPLICATIONS

@node Card applications
@section Description of card applications

@command{scdaemon} supports the card applications as described below.

@menu
* OpenPGP Card::          The OpenPGP card application
* NKS Card::              The Telesec NetKey card application
* DINSIG Card::           The DINSIG card application
* PKCS#15 Card::          The PKCS#15 card application
@end menu

@node OpenPGP Card
@subsection The OpenPGP card application ``openpgp''

This application is currently only used by @command{gpg} but may in
future also be useful with @command{gpgsm}. 

The specification for such a card is available at
@uref{http://g10code.com/docs/openpgp-card-1.0.pdf}.

@node NKS Card
@subsection 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 @command{gpgsm}.

@node DINSIG Card
@subsection The DINSIG card application ``dinsig''

This is an application as described in the German draft standard
@emph{DIN V 66291-1}.  It is intended to be used by cards supporteing
the German signature law and its bylaws (SigG and SigV).

@node PKCS#15 Card
@subsection The PKCS#15 card application ``p15''

This is common fraqmework for smart card applications; support is only
available if compiled with support for the OpenSC library.  It is used
by @command{gpgsm}.



@c 
@c  Examples
@c
@node Scdaemon Examples
@section Examples

@c man begin EXAMPLES

@example
$ scdaemon --server -v
@end example

@c man end

@c 
@c  Assuan Protocol
@c
@node Scdaemon Protocol
@section Scdaemon's Assuan Protocol

The SC-Daemon should be started by the system to provide access to
external tokens.  Using Smartcards on a multi-user system does not
make much sense expcet for system services, but in this case no
regular user accounts are hosted on the machine.

A client connects to the SC-Daemon by connecting to the socket named
@file{/var/run/scdaemon/socket}, configuration information is read from
@var{/etc/scdaemon.conf}

Each connection acts as one session, SC-Daemon takes care of
syncronizing access to a token between sessions.

@menu
* Scdaemon SERIALNO::     Return the serial number.
* Scdaemon LEARN::        Read all useful information from the card.
* Scdaemon READCERT::     Return a certificate.
* Scdaemon READKEY::      Return a public key.
* Scdaemon PKSIGN::       Signing data with a Smartcard.
* Scdaemon PKDECRYPT::    Decrypting data with a Smartcard.
* Scdaemon GETATTR::      Read an attribute's value.
* Scdaemon SETATTR::      Update an attribute's value.
* Scdaemon GENKEY::       Generate a new key on-card.
* Scdaemon RANDOM::       Return random bytes generate on-card.
* Scdaemon PASSWD::       Change PINs.
* Scdaemon CHECKPIN::     Perform a VERIFY operation.
@end menu

@node Scdaemon SERIALNO 
@subsection Return the serial number

This command should be used to check for the presence of a card.  It is
special in that it can be used to reset the card.  Most other commands
will return an error when a card change has been detected and the use of
this function is therefore required.

Background: We want to keep the client clear of handling card changes
between operations; i.e. the client can assume that all operations are
done on the same card unless he call this function.

@example
  SERIALNO
@end example

Return the serial number of the card using a status reponse like:

@example
  S SERIALNO D27600000000000000000000 0
@end example

The trailing 0 should be ignored for now, it is reserved for a future
extension.  The serial number is the hex encoded value identified by 
the @code{0x5A} tag in the GDO file (FIX=0x2F02).



@node Scdaemon LEARN
@subsection Read all useful information from the card

@example
  LEARN [--force]
@end example

Learn all useful information of the currently inserted card.  When
used without the force options, the command might do an INQUIRE
like this:

@example
      INQUIRE KNOWNCARDP <hexstring_with_serialNumber> <timestamp>
@end example

The client should just send an @code{END} if the processing should go on
or a @code{CANCEL} to force the function to terminate with a cancel
error message.  The response of this command is a list of status lines
formatted as this:

@example
     S KEYPAIRINFO @var{hexstring_with_keygrip} @var{hexstring_with_id}
@end example

If there is no certificate yet stored on the card a single "X" is
returned in @var{hexstring_with_keygrip}.

@node Scdaemon READCERT
@subsection Return a certificate

@example
 READCERT @var{hexified_certid}
@end example

This function is used to read a certificate identified by
@var{hexified_certid} from the card.


@node Scdaemon READKEY
@subsection Return a public key

@example
READKEY @var{hexified_certid}
@end example

Return the public key for the given cert or key ID as an standard
S-Expression. 



@node Scdaemon PKSIGN
@subsection Signing data with a Smartcard

To sign some data the caller should use the command

@example
 SETDATA @var{hexstring}
@end example

to tell @command{scdaemon} about the data to be signed.  The data must be given in
hex notation.  The actual signing is done using the command

@example
  PKSIGN @var{keyid}
@end example

where @var{keyid} is the hexified ID of the key to be used.  The key id
may have been retrieved using the command @code{LEARN}.


@node Scdaemon PKDECRYPT
@subsection Decrypting data with a Smartcard

To decrypt some data the caller should use the command

@example
 SETDATA @var{hexstring}
@end example

to tell @command{scdaemon} about the data to be decrypted.  The data
must be given in hex notation.  The actual decryption is then done
using the command

@example
  PKDECRYPT @var{keyid}
@end example

where @var{keyid} is the hexified ID of the key to be used.


@node Scdaemon GETATTR
@subsection Read an attribute's value.

TO BE WRITTEN.

@node Scdaemon SETATTR
@subsection Update an attribute's value.

TO BE WRITTEN.

@node Scdaemon GENKEY
@subsection Generate a new key on-card.

TO BE WRITTEN.

@node Scdaemon RANDOM
@subsection Return random bytes generate on-card.

TO BE WRITTEN.


@node Scdaemon PASSWD
@subsection Change PINs.

TO BE WRITTEN.


@node Scdaemon CHECKPIN
@subsection Perform a VERIFY operation.

TO BE WRITTEN.