Update documentation for scdtotp

Add a draft man page for scdtotp and update the README file
to mention the new program.

README

@@ -23,6 +23,19 @@ of communicating with the smartcard, then runs with the privileges on
 the calling user.
 
 
+Scdtotp - Generate time-based OTP from an OpenPGP smartcard
+-----------------------------------------------------------
+Scdtotp uses an OpenPGP smartcard as a poor man’s one-time password
+generator token. It generates time-based one-time password (TOTP)
+as per RFC 6238, based on a key it expects to find in the private
+data object of the inserted OpenPGP smartcard.
+
+Note that contrary to a true password generator token, the key cannot
+remain only on the smartcard, it has to be sent to the computer so
+that scdtotp can derive the password from it. Thus it cannot provide
+the same level of security.
+
+
 Copying
 -------
 Scdtools is distributed under the terms of the GNU General Public

configure.ac

@@ -35,7 +35,7 @@ AM_PATH_GPG_ERROR([1.11],
 
 dnl Output files
 AC_CONFIG_FILES([Makefile lib/Makefile src/Makefile
-                 man/Makefile man/scdrand.1])
+                 man/Makefile man/scdrand.1 man/scdtotp.1])
 AC_OUTPUT
 
 dnl Summary

man/Makefile.am

@@ -1 +1 @@
-man_MANS = scdrand.1
+man_MANS = scdrand.1 scdtotp.1

man/scdtotp.1.in

@@ -0,0 +1,69 @@
+.TH SCDTOTP 18/12/2014 "scdtools @PACKAGE_VERSION@"
+
+.SH NAME
+scdtotp \- Generate one-time passwords from an OpenPGP smartcard
+
+.SH SYNOPSIS
+.SY scdtotp
+.RB [ \-h | --help ]
+.RB [ \-v | --version ]
+.RB [ \-t | --time
+.IR seconds ]
+.RB [ \-s | --step
+.IR N ]
+.RB [ \-d | --digits
+.IR N ]
+.YS
+
+.SH DESCRIPTION
+.PP
+.B scdtotp
+generates time-based one-time passwords (TOTP) as per
+RFC 6238 derived from a key it finds in the private data
+object 1 (Private DO 1) of an OpenPGP smartcard.
+.PP
+The program depends on
+.I scdaemon
+(part of GnuPG) to interact with a card reader and the
+card itself.
+
+.SH OPTIONS
+.TP
+.BR -h ", " --help
+Display the help message.
+.TP
+.BR -v ", " --version
+Display the version message.
+.TP
+.BR -t ", " --time " " \fiseconds\fR
+Generate password for the specified time in seconds
+instead of current time.
+.TP
+.BR -s ", " --step " " \fiN\fR
+Specify the value of the time step parameter.
+.TP
+.BR -d ", " --digits " " \fiN\fR
+Output a password of
+.I N
+digits.
+
+.SH REPORTING BUGS
+.PP
+Report bugs to
+.MT @PACKAGE_BUGREPORT@
+Damien Goutte-Gattat
+.ME .
+
+.SH SEE ALSO
+.BR scdaemon (1),
+.BR oathtool (1)
+
+.SH COPYRIGHT
+.ad l
+.PP
+Copyright \(co 2014 Damien Goutte-Gattat
+.PP
+This program is released under the GNU General Public License.
+See the COPYING file in the source distribution or
+.UR http://www.gnu.org/licenses/gpl.html
+.UE .