.\"
.\" gen_koch_sig.1 - the *roff document processor man page source
.\"
.TH gen_koch_sig 1 "98/06/30" "Watermarking, Version 1.0"
.SH NAME
.B gen_koch_sig
\- a program to generate a signature for
the
.B wm_koch_e
watermarking program
.SH SYNOPSIS
.B gen_koch_sig
[
.B \-h
]
[
.BI \-n \ number
]
[
.BI \-o \ file
]
[
.BI \-q \ number
]
[
.BI \-s \ number
]
[
.IR file
]
.SH DESCRIPTION
.B gen_koch_sig
is a program to generate a signature to be
embedded with the
.B wm_koch_e
watermarking program and extracted with the
.B wm_koch_d
program. The
.B cmp_koch_sig
program is used to compare and test an
extracted signature with the original signature.
.PP
Please refer to E. Koch's paper "Towards Robust and Hidden
Image Copyright", 1995, to get an idea about the algorithm.
.PP
.SH OPTIONS
.TP
.B \-h
Print a help message.
.TP
.BI \-n \ number
Limit the signature length to
.I number
bits (0 <
.I number
<= 1024) unless reading from standard input. When reading from
standard input, the signature is terminated by the first
carriage return character.
.TP
.BI \-o \ file
Output signature to the specified
.I file
instead of standard output.
.TP
.BI \-q \ number
Quality/robustness factor used to embed signature into image.
Default value: 3.0.
.TP
.BI \-s \ number
Specify a seed value to initialize the pseudo-random number
generator; if not specified, time and pid (process id) are used
to initialize the pseudo-random number generator.
.TP
.IR file
Input file to read raw signature data from. Default: standard
input.
.PP
.SH OUTPUT
The output file has the following format:
.TP
.B KCSG
Magic to identify file type.
.TP
.I number
The length of the signature in bits.
.TP
.I number
The quality/robustness factor.
.TP
.I number
The seed value for the pseudo-random number generator.
.TP
.I string
The actual signature bytes.
.PP
.SH AUTHOR
Peter Meerwald. Email bug reports to pmeerw@cosy.sbg.ac.at.
.SH AVAILABILITY
The most recent released version of
.B gen_koch_sig
is always available
at http://www.cosy.sbg.ac.at/~pmeerw/Watermarking or via anonymous ftp from ftp.cosy.sbg.ac.at in the
directory /pub/people/pmeerw/Watermarking.
.SH "SEE ALSO"
.BR wm_koch_e
(1),
.BR wm_koch_d
(1),
.BR cmp_koch_sig
(1)