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