cyberchef/src/core/operations/AsconDecrypt.mjs

113 lines
3.9 KiB
JavaScript

/**
* @author Medjedtxm
* @copyright Crown Copyright 2025
* @license Apache-2.0
*/
import Operation from "../Operation.mjs";
import OperationError from "../errors/OperationError.mjs";
import Utils from "../Utils.mjs";
import { toHexFast } from "../lib/Hex.mjs";
import JsAscon from "js-ascon";
/**
* Ascon Decrypt operation
*/
class AsconDecrypt extends Operation {
/**
* AsconDecrypt constructor
*/
constructor() {
super();
this.name = "Ascon Decrypt";
this.module = "Ciphers";
this.description = "Ascon-AEAD128 authenticated decryption as standardised in NIST SP 800-232. Decrypts ciphertext and verifies the authentication tag. Decryption will fail if the ciphertext or associated data has been tampered with.<br><br><b>Key:</b> Must be exactly 16 bytes (128 bits).<br><br><b>Nonce:</b> Must be exactly 16 bytes (128 bits). Must match the nonce used during encryption.<br><br><b>Associated Data:</b> Must match the associated data used during encryption. Any mismatch will cause authentication failure.";
this.infoURL = "https://wikipedia.org/wiki/Ascon_(cipher)";
this.inputType = "string";
this.outputType = "string";
this.args = [
{
"name": "Key",
"type": "toggleString",
"value": "",
"toggleValues": ["Hex", "UTF8", "Latin1", "Base64"]
},
{
"name": "Nonce",
"type": "toggleString",
"value": "",
"toggleValues": ["Hex", "UTF8", "Latin1", "Base64"]
},
{
"name": "Associated Data",
"type": "toggleString",
"value": "",
"toggleValues": ["Hex", "UTF8", "Latin1", "Base64"]
},
{
"name": "Input",
"type": "option",
"value": ["Hex", "Raw"]
},
{
"name": "Output",
"type": "option",
"value": ["Raw", "Hex"]
}
];
}
/**
* @param {string} input
* @param {Object[]} args
* @returns {string}
* @throws {OperationError} if invalid key or nonce length, or authentication fails
*/
run(input, args) {
const key = Utils.convertToByteArray(args[0].string, args[0].option),
nonce = Utils.convertToByteArray(args[1].string, args[1].option),
ad = Utils.convertToByteArray(args[2].string, args[2].option),
inputType = args[3],
outputType = args[4];
if (key.length !== 16) {
throw new OperationError(`Invalid key length: ${key.length} bytes.
Ascon-AEAD128 requires a key of exactly 16 bytes (128 bits).`);
}
if (nonce.length !== 16) {
throw new OperationError(`Invalid nonce length: ${nonce.length} bytes.
Ascon-AEAD128 requires a nonce of exactly 16 bytes (128 bits).`);
}
// Convert input to byte array
const inputData = Utils.convertToByteArray(input, inputType);
const keyUint8 = new Uint8Array(key);
const nonceUint8 = new Uint8Array(nonce);
const adUint8 = new Uint8Array(ad);
const ciphertextUint8 = new Uint8Array(inputData);
try {
// Decrypt (returns Uint8Array containing plaintext)
const plaintext = JsAscon.decrypt(keyUint8, nonceUint8, adUint8, ciphertextUint8);
// Return in requested format
if (outputType === "Hex") {
return toHexFast(plaintext);
} else {
return Utils.arrayBufferToStr(Uint8Array.from(plaintext).buffer);
}
} catch (e) {
throw new OperationError("Unable to decrypt: authentication failed. The ciphertext, key, nonce, or associated data may be incorrect or tampered with.");
}
}
}
export default AsconDecrypt;