CyberChef/src/core/operations/FromBase58.mjs

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/**
* @author tlwr [toby@toby.codes]
* @copyright Crown Copyright 2017
* @license Apache-2.0
*/
import Operation from "../Operation.mjs";
import Utils from "../Utils.mjs";
import OperationError from "../errors/OperationError.mjs";
import {ALPHABET_OPTIONS} from "../lib/Base58.mjs";
/**
* From Base58 operation
*/
class FromBase58 extends Operation {
/**
* FromBase58 constructor
*/
constructor() {
super();
this.name = "From Base58";
this.module = "Default";
this.description = "Base58 (similar to Base64) is a notation for encoding arbitrary byte data. It differs from Base64 by removing easily misread characters (i.e. l, I, 0 and O) to improve human readability.<br><br>This operation decodes data from an ASCII string (with an alphabet of your choosing, presets included) back into its raw form.<br><br>e.g. <code>StV1DL6CwTryKyV</code> becomes <code>hello world</code><br><br>Base58 is commonly used in cryptocurrencies (Bitcoin, Ripple, etc).";
this.infoURL = "https://wikipedia.org/wiki/Base58";
this.inputType = "string";
this.outputType = "byteArray";
this.args = [
{
"name": "Alphabet",
"type": "editableOption",
"value": ALPHABET_OPTIONS
},
{
"name": "Remove non-alphabet chars",
"type": "boolean",
"value": true
}
];
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this.checks = [
{
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pattern: "^[1-9A-HJ-NP-Za-km-z]{20,}$",
flags: "",
args: ["123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz", false]
},
{
pattern: "^[1-9A-HJ-NP-Za-km-z]{20,}$",
flags: "",
args: ["rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz", false]
},
];
}
/**
* @param {string} input
* @param {Object[]} args
* @returns {byteArray}
*/
run(input, args) {
let alphabet = args[0] || ALPHABET_OPTIONS[0].value;
const removeNonAlphaChars = args[1] === undefined ? true : args[1],
result = [];
alphabet = Utils.expandAlphRange(alphabet).join("");
if (alphabet.length !== 58 ||
[].unique.call(alphabet).length !== 58) {
throw new OperationError("Alphabet must be of length 58");
}
if (input.length === 0) return [];
let zeroPrefix = 0;
for (let i = 0; i < input.length && input[i] === alphabet[0]; i++) {
zeroPrefix++;
}
[].forEach.call(input, function(c, charIndex) {
const index = alphabet.indexOf(c);
if (index === -1) {
if (removeNonAlphaChars) {
return;
} else {
throw new OperationError(`Char '${c}' at position ${charIndex} not in alphabet`);
}
}
let carry = index;
for (let i = 0; i < result.length; i++) {
carry += result[i] * 58;
result[i] = carry & 0xFF;
carry = carry >> 8;
}
while (carry > 0) {
result.push(carry & 0xFF);
carry = carry >> 8;
}
});
while (zeroPrefix--) {
result.push(0);
}
return result.reverse();
}
}
export default FromBase58;