Hidden Communications: The Effectiveness of Steganography Gregory Taylor (ichbineingenie@gmail.com) – Cary High School Summer Ventures in Science and Math – Visualization and Image Processing Appalachian State University – July 2009 Dr. Rahman Tashakkori, Mr. Jere Miles & Ms. Biva Shrestha

Introduction What is steganography? Dates back to the Greeks Centered around avoiding detection Many different types

Methods Create a steganographic image Alter the image using different filters Attempt to re-extract the message Analyze how much of the message remained intact and the effects of the filters

The Image Original image was color Made smaller and grayscale Final product Create the message Hello there! If you are reading this, then you probably already know what this message is about. If you don't know what this message is about, then just stop reading right now. I'm serious. This message is not for you. The purpose of writing this was to communicate the details of a secret plot. If you are not a part of this secret plot, once again, you should stop reading now. (This space is empty) (This space is still empty) Stop it now. Really. Reading this message will not give you some sort of incredible knowledge that you will be able to use in your daily life. This stuff is top secret. For realz. Look! I can talk like a gangsta. Fo shizzle! (...) (...) Why has my failure at being cool not yet scared you away? It always works! By the way, I'm not even going to disclose my secret plot in this message. Why would I? You're obviously reading this when you shouldn't be. If I disclose now, then you might ruin our totally awesome plan! So, I'm not going to tell you. The End...............,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,. Still not telling you.... ;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;:;: It's the last paragraph. It's the last chance to disclose. Will I? Does it even matter now? I guess it depends on you now. *

Create and Test the Stego-Object Encrypt the message Decrypt the message If full message is the result, methods are confirmed functional Save as a text image Extract least significant digit binary Compare with the stego-message binary Make appropriate changes Resave as a new text image Open text image Extract least significant digit binary Plug into binary to ASCII converter Record results

Filter and Test A total of 14 filters used, but only 12 useful Extract the message from each filtered image Record results Save as a PNG file Enhance contrast on the image* Save as a JPG file Raise the contrast of the images by an even value Save as a GIF file Save as a BMP file Raise the contrast of the image by an odd value Save as a BMP file using GIMP* Sharpen the image Lower the brightness of the image Blur the image Raise the brightness of the image Use edge detection on the image Add random noise to the image

Results Different Binary Characters Different Binary Percentage Different ASCII Characters Different ASCII Percentage Raw Stego 0.00% PNG 3104 31.04% 802 64.16% JPG 4743 47.43% 1226 98.08% GIF BMP BMP GIMP* Sharpen 5531 55.31% 1204 96.32% Blur 4838 48.38% 1242 99.36% Edge Detection 4975 49.75% 1243 99.44% Enhance Contrast* Raise Contrast (E) 7249 72.49% 1220 97.60% Raise Contrast (O) 2761 27.61% 780 62.40% Darken 3268 32.68% 770 61.60% Brighten 3172 31.72% 766 61.28% Noise 188 1.88% 128 10.24%

Results

Results PNG JPG Contrast (O) Contrast (E)

Conclusions Steganography effective in hiding messages Active filtering as seen here easily destroys messages hidden in this way Steganography an active growing field Basic encryption

Thank you! Dr. Rahman Tashakkori Acknowledgements Mr. Jere Miles Ms. Biva Shrestha