Implementation of Least Significant Bit Image Steganography and its Steganalaysis By: Deniz Oran Fourth Quarter

Goals To conceal a text message into a "carrier" image with Least Significant Bit Steganography To detect that an image has been compromised or altered and to extract that message To extend the method to apply to various image formats To make the program usable with a Graphical User Interface (GUI)

Literally means "concealed writing" in Greek Opposite of cryptography, in which a message is made unintelligible, but transmitted through public means Steganography is the concealment of the fact that a message is even being transferred. What is Steganography?

Historical Methods Shaving hair Wax tablets Jargon Cardano grille Invisible Inks Thermo-activated inks Micro dots Enigma Machine All of the above have been used for espionage and for coordinating attacks on other bodies.

Current Method Hiding an entire text or image binary in either an image or audio “carrier” using Least Significant Bit encoding Previously done as a Senior Technology Lab using the same technique with.wav audio files in There is currently no established method for encoding something with steganography because better encoding methods translate to lower carrier image capacity. There is no established method for universally detecting steganography because of the variety of methods.

Least Significant Bit Encoding Images on computers are made out of pixels Each pixel is represented by three byte s Each byte is composed of eight bits or 1s and 0s The second set of bytes represents the encoded ASCII character “G” ( )

Program Design in JAVA Create a GUI Dropdown menu Input a suspected image Attempt to detect if it has been compromised Place the two image next to each other for visual comparison when extraction is finished.

Inputing the Image Read the binary of the image using Buffered Reader, DataBufferByte, and WritableRaster into a three dimensional array (data cube) with the row, column and corresponding color value (depends on image format). Alter every Least Significant Bit in each byte in order to spell out the word. The ASCII values are understood by DataBufferByte instead of having me define each one. Save the altered image because it is ready to be sent Saving should be done using a “lossless” image standard because this form of steganography exploits the “noise” of an image. Therefore,.PNG is a good start.

Steganalysis Detecting a message encoded using steganography is only feasible if the original image is available or if the exact encoding method is known. The program will still be able to detect if an image has been compromised by converting the suspected image into hexadecimal but the message may not be extracted. This method won’t work if a proper LSB is done, since the encoding starts after the data for the hex tags, thus not altering them.

Decoding Just attempt to reverse the process of Least Significant Bit encoding. This method is always tried by commercial software but hardly works if the LSB is done differently. The suspected image is inputted, converted to binary, the length of the message was hidden in the first 32 bytes, that length is the parameter for the for-loop which traverses the rest of the image extracting the least significant bits in the same manner they were isolated when they were inserted The output is the original ASCII message inputted by the first user

Possible Problems Steganography is an increasingly complex field because of new algorithms and unique ways of analyzing images There are many methods to inconspicuously hide an image or text message with computer science, some are less complex (microdots) and some use higher level mathematical algorithms (stochastic modulation) The Least Significant Bit method is an established method and can be detected at 80% accuracy using highly advanced math but not the human eye

Learned Concepts How images of various formats are constructed, especially.PNG. How to determine a file's extension using JAVA How to manipulate binary code and understanding the role of bits within bytes. Binary operations such as AND, OR, ADD. Various methods of Steganography and Steganalysis and which are the most effective

Future Projects Extend the program to work with other image formats and improve the algorithms susceptibility to common detection methods (using padding and random byte locations) Extend the steganography to another medium Pairing the steganography with a simple encryption algorithm