mirror of https://github.com/gchq/CyberChef.git
84 lines
2.5 KiB
JavaScript
84 lines
2.5 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 { runHash } from "../lib/Hash.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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* Randomize Colour Palette operation
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*/
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class RandomizeColourPalette extends Operation {
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/**
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* RandomizeColourPalette constructor
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*/
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constructor() {
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super();
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this.name = "Randomize Colour Palette";
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this.module = "Image";
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this.description = "Randomizes each colour in an image's colour palette. This can often reveal text or symbols that were previously a very similar colour to their surroundings, a technique sometimes used in Steganography.";
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this.infoURL = "https://wikipedia.org/wiki/Indexed_color";
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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: "Seed",
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type: "string",
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value: ""
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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 seed = args[0] || (Math.random().toString().substr(2)),
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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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let rgbString, rgbHash, rgbHex;
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parsedImage.scan(0, 0, width, height, function(x, y, idx) {
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rgbString = this.bitmap.data.slice(idx, idx+3).join(".");
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rgbHash = runHash("md5", Utils.strToArrayBuffer(seed + rgbString));
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rgbHex = rgbHash.substr(0, 6) + "ff";
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parsedImage.setPixelColor(parseInt(rgbHex, 16), x, y);
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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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export default RandomizeColourPalette;
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