Phase1 - An Image Steganography Decoder

Overview

The Phase1 program decodes hidden messages (text or images) embedded within a source image using steganographic techniques. It supports decoding text and images by extracting least significant bits (LSBs) from pixel channels. The program also includes utilities to analyze raster image data. This project was a collaboration between Ahsan Rhandawa and I.

In addition to the standard Java-based command-line usage, there is a standalone GUI tool (Phase1.jar) for easier interaction with the program.

Features

• Decode hidden text messages from images.
• Decode hidden images embedded in a source image.
• Analyze preliminary data from image rasters.
• Flexible command-line options for decoding configurations.
• Standalone GUI Tool (Phase1.jar) for visual interaction.
• Java Command-Line Tool for users who prefer the terminal.

Requirements

• For Java Command-Line Tool:
• Java Development Kit (JDK) 8 or higher.

• Java AWT and ImageIO libraries (included in the standard JDK).

• For Standalone GUI Tool (Phase1.jar):

• Java Runtime Environment (JRE) version 8 or higher (bundled with Phase1.jar).

Usage

1. Download the zip of the repository and extract it

2. Navigate to the /src subfolder

3. For Java Command-Line Tool:

Open a terminal in this directory and run the command with these command-line arguments:

java Phase1 [filename] [HiddenMessageType] [LRTBOrTBLR] [rORfORsLength] [rORfORsData] [numberOfSignificantBits] [ArrayOFleastSignificantBits] [numberOfPixelChannels] [arrayOfPixelChannels]

4. For Standalone GUI Tool (Phase1.jar):

If you'd prefer a GUI, you can use the Phase1.jar file. To run the GUI tool:

• Windows, Mac, or Linux: Download the Phase1.jar file and run the following command in the terminal (or double-click the file on supported systems):
  bash java -jar Phase1.jar

The GUI will allow you to interact with the program through a more user-friendly interface, eliminating the need for command-line arguments.

Parameters (Command-Line Tool)

• filename: Path to the input image file.
• HiddenMessageType: Type of the hidden message (text, png, or lw).
• LRTBOrTBLR: Specifies the reading order:
• LRTB: Left-to-right, top-to-bottom.
• TBLR: Top-to-bottom, left-to-right.
• rORfORsLength: Specifies how to handle the length of the hidden message:
• r: Reverse bits.
• f: Flip bits.
• s: Keep bits straight.
• rORfORsData: Specifies how to handle the data:
• r: Reverse bits.
• f: Flip bits.
• s: Keep bits straight.
• numberOfSignificantBits: Number of significant bits in the input data.
• ArrayOFleastSignificantBits: Array of LSB indices for bit extraction.
• numberOfPixelChannels: Number of pixel channels used for decoding.
• arrayOfPixelChannels: Array specifying pixel channels to decode from.

Example (Command-Line Tool)

java Phase1 example.png text LRTB r s 1 0 3 0 1 2

Hidden Message Types

1. text: Decodes hidden text messages.
2. png: Decodes a hidden image and outputs it as a PNG file.
3. lw: Extracts preliminary raster data for analysis.

Key Methods

getNextIntFromImage

Extracts the next 32 bits as an integer from the image based on the configured reading order and bit manipulations.

getTextData

Extracts and decodes hidden text from the image based on the provided length.

getImageData

Decodes a hidden image by extracting pixel data and creating a new image.

getImageWithLeastSignificantBit

Generates an image visualizing the least significant bits of the source image's pixels.

Output

• Text decoding: Prints the hidden message to the console.
• Image decoding: Outputs the decoded image to the Decoding/ directory.
• Raster analysis: Prints preliminary raster data for LSB configurations.

Notes

• Ensure the input image is accessible and in a supported format (e.g., PNG).
• The output directory for decoded images (Decoding/) must exist or be created manually.
• The GUI version (Phase1.jar) does not require command-line arguments, providing an easier way to interact with the tool.
• The command-line tool offers flexibility for advanced users who want to pass specific decoding configurations.

Development

File Structure

• Phase1.java: Main program file with all decoding logic.
• Decoding/: Output directory for decoded images.
• Phase1.jar: Standalone GUI tool packaged with Java Runtime Environment (JRE).

Dependencies

• Java Standard Library (AWT, ImageIO).
• For Standalone GUI Tool: Bundled JRE in Phase1.jar.

Limitations

• Only supports decoding messages embedded using specific LSB steganography techniques.
• Does not include error handling for unsupported image types or corrupted input.
• I welcome any new contributions to my testing script.

License

This project is licensed under the MIT License.