JPSEEK and JPHIDE are 2 programs that allows you to hide a file in a jpeg visual image. There are lots of versions of similar programs available on the internet but JPHIDE and JPSEEK are rather special.
The design objective was not simply to hide a file but rather to do this in such a way that it is impossible to prove that the host file contains a hidden file. Given a typical visual image, a low insertion rate (under 5%) and the absence of the original file, it is not possible to conclude with any worthwhile certainty that the host file contains inserted data.
As the insertion percentage increases the statistical nature of the jpeg coefficients differs from "normal" to the extent that it raises suspicion. Above 15% the effects begin to become visible to the naked eye. Of course some images are much better than others when used a host file - plenty of fine detail is good. A cloudless blue sky over a snow covered ski paradise is bad. A waterfall in a forest is probably ideal.
jphide input-jpeg-file output-jpeg-file file-to-be-hidden
jpseek input-jpeg-file output-hidden-file
Building the programs:
Get the sources for the jpeg library jpeg-6a.
I got mine from a RedHat cd.
Compile them following the instructions that came with them.
Check them out - there is a "make test".
Use tar to put the new programs into the directory containing
the standard jpeg-6a sources:
tar -xzf jphs.tgz
Patch the makefile: