Ubuntu Manpage: stegsnow - whitespace steganography program

Provided by: stegsnow_20130616-2_amd64

NAME

       stegsnow - whitespace steganography program

SYNOPSIS

       stegsnow  [  -CQS  ] [ -h | --help ] [ -V | --version ] [ -p passwd ] [ -l line-len ] [ -f
       file | -m message ] [ infile [ outfile ]]

DESCRIPTION

stegsnow is a program for concealing messages in text files by appending tabs and spaces
on the end of lines, and for extracting messages from files containing hidden messages.
Tabs and spaces are invisible to most text viewers, hence the steganographic nature of
this encoding scheme.

The data is concealed in the text file by appending sequences of up to 7 spaces,
interspersed with tabs. This usually allows 3 bits to be stored every 8 columns. An
alternative encoding scheme, using alternating spaces and tabs to represent zeroes and
ones, was rejected because, although it used fewer bytes, it required more columns per bit
(4.5 vs 2.67).

The start of the data is indicated by an appended tab character, which allows the
insertion of mail and news headers without corrupting the data.

stegsnow provides rudimentary compression, using Huffman tables optimised for English
text. However, if the data is not text, or if there is a lot of data, the use of the
built-in compression is not recommended, since an external compression program such as
compress or gzip will do a much better job.

Encryption is also provided, using the ICE encryption algorithm in 1-bit cipher-feedback
(CFB) mode. Because of ICE's arbitrary key size, passwords of any length up to 1170
characters are supported (since only 7 bits of each character are used, keys up to
1024-bytes are supported).

If a message string or message file are specified on the command-line, stegsnow will
attempt to conceal the message in the file infile if specified, or standard input
otherwise. The resulting file will be written to outfile if specified, or standard output
if not.

If no message string is provided, stegsnow attempts to extract a message from the input
file. The result is written to the output file or standard output.

OPTIONS

       -C     Compress the data if concealing, or uncompress it if extracting.

       -f message-file
              The contents of this file will be concealed in the input text file.

       -l line-len
              When appending whitespace, stegsnow will always produce  lines  shorter  than  this
              value. By default it is set to 80.

       -m message-string
              The  contents  of this string will be concealed in the input text file.  Note that,
              unless a newline is somehow included in the string, a newline will not  be  printed
              when the message is extracted.

       -p password
              If  this  is set, the data will be encrypted with this password during concealment,
              or decrypted during extraction.

       -Q     Quiet mode. If  not  set,  the  program  reports  statistics  such  as  compression
              percentages and amount of available storage space used.

       -S     Report  on the approximate amount of space available for hidden message in the text
              file. Line length is taken into account, but other options are ignored.

       -V, --version
              Display usage information and exit.

       -h, --help
              Display usage information and exit.

EXAMPLES

       The following command will conceal the message "I am  lying"  in  the  file  infile,  with
       compression,  and  encrypted  with  the password "hello world". The resulting text will be
       stored in outfile.

              stegsnow -C -m "I am lying" -p "hello world" infile outfile

       To extract the message, the command would be

              stegsnow -C -p "hello world" outfile

       Note that the resulting message will not be terminated by a newline.

       To prevent line wrap if text with concealed whitespace is likely to be indented by mail or
       news readers, a line length of 72 or less can be used.

              stegsnow -C -l 72 -m "I am lying" infile outfile

       The approximate storage capacity of a file can be determined with the -S option.

              stegsnow -S -l 72 infile

AUTHOR