mirror of https://github.com/gchq/CyberChef.git
83 lines
2.2 KiB
JavaScript
83 lines
2.2 KiB
JavaScript
/**
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* Cipher functions.
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*
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* @author Matt C [matt@artemisbot.uk]
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* @author n1474335 [n1474335@gmail.com]
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*
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* @copyright Crown Copyright 2018
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* @license Apache-2.0
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*
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*/
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import OperationError from "../errors/OperationError.mjs";
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import CryptoJS from "crypto-js";
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/**
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* Affine Cipher Encode operation.
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*
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* @author Matt C [matt@artemisbot.uk]
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* @param {string} input
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* @param {Object[]} args
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* @returns {string}
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*/
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export function affineEncode(input, args) {
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const alphabet = "abcdefghijklmnopqrstuvwxyz",
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a = args[0],
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b = args[1];
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let output = "";
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if (!/^\+?(0|[1-9]\d*)$/.test(a) || !/^\+?(0|[1-9]\d*)$/.test(b)) {
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throw new OperationError("The values of a and b can only be integers.");
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}
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for (let i = 0; i < input.length; i++) {
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if (alphabet.indexOf(input[i]) >= 0) {
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// Uses the affine function ax+b % m = y (where m is length of the alphabet)
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output += alphabet[((a * alphabet.indexOf(input[i])) + b) % 26];
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} else if (alphabet.indexOf(input[i].toLowerCase()) >= 0) {
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// Same as above, accounting for uppercase
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output += alphabet[((a * alphabet.indexOf(input[i].toLowerCase())) + b) % 26].toUpperCase();
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} else {
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// Non-alphabetic characters
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output += input[i];
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}
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}
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return output;
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}
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/**
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* Generates a polybius square for the given keyword
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*
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* @private
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* @author Matt C [matt@artemisbot.uk]
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* @param {string} keyword - Must be upper case
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* @returns {string}
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*/
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export function genPolybiusSquare (keyword) {
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const alpha = "ABCDEFGHIKLMNOPQRSTUVWXYZ",
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polArray = `${keyword}${alpha}`.split("").unique(),
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polybius = [];
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for (let i = 0; i < 5; i++) {
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polybius[i] = polArray.slice(i*5, i*5 + 5);
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}
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return polybius;
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}
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/**
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* A mapping of string formats to their classes in the CryptoJS library.
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*
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* @private
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* @constant
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*/
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export const format = {
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"Hex": CryptoJS.enc.Hex,
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"Base64": CryptoJS.enc.Base64,
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"UTF8": CryptoJS.enc.Utf8,
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"UTF16": CryptoJS.enc.Utf16,
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"UTF16LE": CryptoJS.enc.Utf16LE,
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"UTF16BE": CryptoJS.enc.Utf16BE,
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"Latin1": CryptoJS.enc.Latin1,
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};
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