(c) 1999-2004 by Niels Provos

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OutGuess - general Information

Data Embedding

Below you can see an example run of OutGuess. The table gives an explanation of the different columns in the output.

$ outguess -k "my secret key" -d hidden.txt demo.jpg out.jpg
Reading demo.jpg....
JPEG compression quality set to 75
Extracting usable bits: 40059 bits
Correctable message size: 21194 bits, 52.91%
Encoded 'snark.bz2': 14712 bits, 1839 bytes
Finding best embedding...
    0:  7467(50.6%)[50.8%], bias  8137(1.09), saved:   -13, total: 18.64%
    1:  7311(49.6%)[49.7%], bias  8079(1.11), saved:     5, total: 18.25%
    4:  7250(49.2%)[49.3%], bias  7906(1.09), saved:    13, total: 18.10%
   59:  7225(49.0%)[49.1%], bias  7889(1.09), saved:    16, total: 18.04%
59, 7225: Embedding data: 14712 in 40059
Bits embedded: 14744, changed: 7225(49.0%)[49.1%], bias: 7889, tot: 40032, skip: 25288
Foiling statistics: corrections: 2590, failed: 1, offset: 122.585494 +- 239.664983
Total bits changed: 15114 (change 7225 + bias 7889)
Storing bitmap into data...
Writing foil/out.jpg....

Seed Changed Bits Bias Saved
The value of the seed for the result line. The number of bits that needed to be changed in the redundant data, and the percentage in regards to the amound of hidden data. The accumulated bias of all changed bits. The bias is a measure for the detectability of the changes. The number of bytes that could be represented without modification of data. The base line is 50%.

Data Retrieval

You can retrieve data from an image in the following way:

$ outguess -k "my secret key" -r out.jpg hidden.txt
Reading out.jpg....
Extracting usable bits:   40059 bits
Steg retrieve: seed: 7225, len: 1839


Supported Systems

OutGuess is known to work on
OpenBSD: i386, alpha, sparc
NetBSD: vax
FreeBSD: i386
Linux: i386, sparc, powerpc, alpha
AIX: RS6000, powerpc
Solaris: ultra sparc
HP-UX: mips
BeOS: works, platform unknown
Mac OS X: powerpc
Windows NT: i386

If you have confirmation that OutGuess also works on other platforms, please send me an email.

Last modified: January 4 2006 03:04:12 PM
Copyright 1999-2008 by Niels Provos