OutGuess
OutGuess by Niels Provos is a steganography tool that hides information in PNM or JPEG files.
OutGuess has been tested on OpenBSD, Linux, Solaris and AIX.
OutGuess Rebirth is a portable Win32 version.
JOutguess Rebirth is a web version.
OutGuess preserves statistics based on frequency counts. As a result, statistical tests based on frequency counts are unable to detect the presence of steganographic content. Before embedding data into an image, OutGuess can determine the maximum message size that can be hidden while still being able to maintain statistics based on frequency counts.
OutGuess uses a generic iterator object to select which bits in the data should be modified. A seed can be used to modify the behavior of the iterator. It is embedded in the data along with the rest of the message. By altering the seed, OutGuess tries to find a sequence of bits that minimizes the number of changes in the data that have to be made.
Additionally, OutGuess allows to hide multiple messages (currently only 2) in the data. Thus, it also provides plausible deniablity. It keeps track of the bits that have been modified previously and locks them. A (23,12,7) Golay code is used for error correction to tolerate collisions on locked bits. Artificial errors are introduced to avoid modifying bits that have a hight bias.
After 0.13b was cracked, Niels Provos released 0.2 which isn't backwards compatible.
A fork called OutGuess Rebirth (OGR) was released in 2013 by Laurent Perch, with some bug fixes and a graphical user interface for Windows.
In November 2018, Debian developer Joao Eriberto Mota Filho imported the source code into a new repository on GitHub to continue development, and since then released some new minor versions that include bug fixes from several people
Links
- Homepage
- Archived OutGuess Rebirth (OGR) homepage
- Resurrecting OutGuess
- JOutguess Rebirth (online version)
- JOutguess Rebirth source code
- Download v0.13b (different format)
- Fridrich, Goljan and Hogea's "Attacking the OutGuess" is capable of reliably detecting images with content embedded by OutGuess
- Higher-level statistical tests detect OutGuess 0.2
- Stegdetect - detects OutGuess 0.13b files
- SSAK - GUI front end for file identification, data carving, hexdump and steganography programs that includes OutGuess v0.13b
- Steganography Toolkit - Docker image with a bunch of steganography tools including OutGuess v0.13b and v0.2
- Aletheia - dictionary attacks
- Wikipedia article
