Re: A revision of my text stego scheme

Am 20.05.2011 18:46, schrieb jbriggs444:

Using line length to encode your stego bits is clumsy. Why not
compute a hash function based on the line and choose a wording
that makes the [let's say] seventeenth bit carry the stego bit
value?

So you fiddle with the wording, case variations, punctuation,
indentation, spacing or whatever on a line of text until the
seventeenth bit in the hash comes out right.

The advantage is that now you are no longer restricted to
transformations that change line length by an odd number
of characters. You can now do arbitrary transformations
(still facing the problem that 50% of these transformations
are likely to leave you with an unchanged value in bit 17).

Another advangage is that you are now free to use either
more than or less than a single line of text per stego bit
and are free to encode more than one stego bit per
plaintext unit.

And you are no longer tied to printable text.

Of course, this is all a grade school exercise of
little or no practical value.

Maybe I gravely misunderstood you. But why do you think that
using a hash function the fiddling is easier than without the
hash function? One has to try different wordings in both cases.
Without the hash function one knows the effect of a change directly.
For example the line length is odd but it should be even because
the stego bit is 0. In that case if one spots e.g. a noun that
has an equivalent word that is longer by 1 character, then the
job is done.

Anyway my scheme can be simply done by anyone, without requiring any
piece of software code:

M. K. Shen
.

Relevant Pages

  • Re: A revision of my text stego scheme
    ... Using line length to encode your stego bits is clumsy. ... compute a hash function based on the line and choose a wording ... So you fiddle with the wording, case variations, punctuation, ... You can now do arbitrary transformations ...
    (sci.crypt)
  • Re: A revision of my text stego scheme
    ... compute a hash function based on the line and choose a wording ... that makes the seventeenth bit carry the stego bit ... transformations that change line length by an odd number ... the set of transformations that fail to preserve, ...
    (sci.crypt)
  • Re: A revision of my text stego scheme
    ... compute a hash function based on the line and choose a wording ... hide the message in, and you are willing to fiddle with wording, word ... Now we fiddle with the text until F ... the link between the text and the message it encodes is unknown. ...
    (sci.crypt)