Concealing within charts: vis-steg

[arranzeyuwang]

vis-steg can conceal information within visualization images via visual steganography methods. It employs an encoder-decoder system to conceal and creak information from charts. You can click its repo for detail.

Its pipeline can be shown as follows.

Features

• Information Encoding and Decoding: A javascript library for embedding information within visualization images.
  The decoding algorithm just relies on the encoded image.
• String and Bits Array Transformation: Converting a string to a bits array and vice versa using UTF8 encoding and decoding.

Installation

$ npm install

Getting Started

• Information Encoding

import { LSBSteg } from './src';

const testLSBSteg = new LSBSteg();
const secretInfo = 'hello';
testLSBSteg.writeLSB({
  imgBitmapData: imgBitmapData,
  imgHeight: img.height,
  imgWidth: img.width,
  secretInfo,
});

• Information Decoding

import { LSBSteg } from './src';

const testLSBSteg = new LSBSteg();
const decodeSecret = testLSBSteg.readLSB({
  imgBitmapData: imgBitmapData,
  imgHeight: img.height,
  imgWidth: img.width,
});

Demo

$ npm run start:demo

See the demos

• Pipeline
• Vis-Image Transformation

Supported Algorithms

• LSB: Least Significant Bit method for image steganography. The binary bits of the secret information were used to replace the bits of container image pixels. The replacing occurs from the least bit to the highest bit to retain the quality of the container image.

  LSB Encode Process

  • Input

  - RGB (or gray) Image
  - Secret String
  

  • Process

  1. Adjust RGB (or gray) image to RGBA form.
  2. Add a head string for further check.
  3. Convert the head string, secret string length, and secret string to bits array, and merge them.
  4. Embed the bits array into the container image. The replacing is from the least bit to the highest bit.

  LSB Decode Process

  • Input

  - RGBA Image
  

  • Process

  1. Read the head string for decoding check.
  2. Read the secret string length (64 bits).
  3. Read the secret string bits array and convert it to string.

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