mirror of https://github.com/gchq/CyberChef.git
108 lines
2.8 KiB
JavaScript
108 lines
2.8 KiB
JavaScript
/**
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* @author Ge0rg3 [georgeomnet+cyberchef@gmail.com]
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* @copyright Crown Copyright 2019
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* @license Apache-2.0
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*/
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import Operation from "../Operation.mjs";
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import OperationError from "../errors/OperationError.mjs";
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import Utils from "../Utils.mjs";
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import { isImage } from "../lib/FileType.mjs";
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import { toBase64 } from "../lib/Base64.mjs";
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import jimp from "jimp";
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/**
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* View Bit Plane operation
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*/
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class ViewBitPlane extends Operation {
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/**
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* ViewBitPlane constructor
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*/
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constructor() {
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super();
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this.name = "View Bit Plane";
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this.module = "Image";
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this.description = "Extracts and displays a bit plane of any given image. These show only a single bit from each pixel, and can be used to hide messages in Steganography.";
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this.infoURL = "https://wikipedia.org/wiki/Bit_plane";
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this.inputType = "ArrayBuffer";
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this.outputType = "ArrayBuffer";
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this.presentType = "html";
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this.args = [
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{
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name: "Colour",
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type: "option",
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value: COLOUR_OPTIONS
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},
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{
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name: "Bit",
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type: "number",
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value: 0
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}
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];
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}
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/**
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* @param {ArrayBuffer} input
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* @param {Object[]} args
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* @returns {ArrayBuffer}
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*/
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async run(input, args) {
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if (!isImage(input)) throw new OperationError("Please enter a valid image file.");
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const [colour, bit] = args,
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parsedImage = await jimp.read(input),
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width = parsedImage.bitmap.width,
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height = parsedImage.bitmap.height,
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colourIndex = COLOUR_OPTIONS.indexOf(colour),
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bitIndex = 7-bit;
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if (bit < 0 || bit > 7) {
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throw new OperationError("Error: Bit argument must be between 0 and 7");
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}
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let pixel, bin, newPixelValue;
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parsedImage.scan(0, 0, width, height, function(x, y, idx) {
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pixel = this.bitmap.data[idx + colourIndex];
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bin = Utils.bin(pixel);
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newPixelValue = 255;
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if (bin.charAt(bitIndex) === "1") newPixelValue = 0;
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for (let i=0; i < 3; i++) {
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this.bitmap.data[idx + i] = newPixelValue;
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}
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this.bitmap.data[idx + 3] = 255;
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});
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const imageBuffer = await parsedImage.getBufferAsync(jimp.AUTO);
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return new Uint8Array(imageBuffer).buffer;
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}
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/**
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* Displays the extracted data as an image for web apps.
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* @param {ArrayBuffer} data
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* @returns {html}
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*/
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present(data) {
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if (!data.byteLength) return "";
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const type = isImage(data);
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return `<img src="data:${type};base64,${toBase64(data)}">`;
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}
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}
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const COLOUR_OPTIONS = [
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"Red",
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"Green",
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"Blue",
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"Alpha"
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];
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export default ViewBitPlane;
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