Secure a byte array in JavaScript by utilizing the crypto js AES ECB algorithm

Question

Secure a byte array in JavaScript by utilizing the crypto js AES ECB algorithm

As I navigate through the world of IoT and encryption, I find myself encountering a challenge with my React Native app that communicates with my MiBand 3. As part of the authentication process, I need to encrypt an array of bytes using the AES/ECB/NoPadding algorithm. To guide me, I have been referring to this code provided by Yogesh Ojha.

However, despite following the steps outlined in the reference code, I suspect that the final step of authentication might be incorrect. After transmitting the encrypted byte array to the MiBand 3, I am facing authentication issues.

The current implementation of the last step involves:

const base_key = [0x01,0x23,0x45,0x67,0x89,0x01,0x22,0x23,0x34,0x45,0x56,0x67,0x78,0x89,0x90,0x02]
console.warn('Obtaining random number...')
const random_number = bytesToString(notification.filter((byte, index) => index > 3))

// Encrypting the key
const key = bytesToString(base_key)
const cipher = CryptoJS.AES.encrypt(random_number,key).toString()

// Step 5) Transmitting encrypted random number
console.warn('Transmitting encrypted random number...')
const request_send_encrypted_key = [0x03,0x00, ...stringToBytes(cipher)]
await BleManager.writeWithoutResponse(miband3, service_uuid, characteristic_uuid, request_send_encrypted_key)

The notification data is filtered because the first 3 bytes indicate the type of notification, which are unnecessary for the encryption process.

To authenticate successfully, I must send the following to the MiBand 3:

const byteArrayToSend = [0x03,0x00, ...encryptedByteArray]

The encryptedByteArray should contain the properly encrypted random number retrieved from the MiBand notification (excluding the first 3 bytes).

In my code, I am utilizing 'crypto-js' library along with 'react-native-ble-manager'. However, I am struggling to implement the AES encryption correctly for sending the bytearray. Can anyone guide me on how to achieve this?

javascript arrays react-native encryption iot

Answer 1

Answer №1

When using CryptoJS for AES encryption, there are several important considerations to keep in mind:

In the provided code snippet, keys and data intended for encryption (random_number) are explicitly designated as arrays. However, CryptoJS utilizes WordArray objects, necessitating a conversion. This can be achieved by easily converting WordArray objects into arrays through hexadecimal strings and vice versa using the provided functions and the CryptoJS Encoders. Alternatively, direct conversion can also be carried out using these functions.
Since the arrays contain arbitrary byte sequences (often not corresponding to readable characters), only suitable encodings such as Base64 or hexadecimal should be used. While it's unclear whether the methods bytesToString and stringToBytes pose any issues as they were not included in the excerpt, CryptoJS enables passing data as either a string or a WordArray, with the latter being employed subsequently.
Notably, if the second parameter in CryptoJS.AES.encrypt is passed as a string, it serves as a passphrase that generates the actual key via a defined algorithm, detailed here. Conversely, when this parameter is interpreted as a key (as evident in the reference code), it must be presented as a WordArray.
The chosen method for encryption is AES/ECB/NoPadding, as specified in the associated Medium article. The absence of padding is permissible due to the encrypted data's length aligning with integer multiples of the AES block size (16 bytes). Should this not hold true, padding would be obligatory.
Following encryption, the output comprises a CipherParams object whereby the encrypted data appears as a WordArray, outlined here.

For successful encryption implementation, the following steps need to be followed:

var CryptoJS = require("crypto-js");

// Key and random number as arrays, e.g.:
var random_numberBA = [0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f];
var keyBA = [0x01, 0x23, 0x45, 0x67, 0x89, 0x01, 0x22, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 0x89, 0x90, 0x02];

// Conversion to WordArrays
var random_numberWA = CryptoJS.enc.Hex.parse(bytesToHex(random_numberBA));
var keyWA = CryptoJS.enc.Hex.parse(bytesToHex(keyBA));

// Encryption
// - random_number as WordArray
// - Key as WordArray
// - ECB-Mode (default: CBC), No-Padding (default: Pkcs7-Padding)
var encryptedCP = CryptoJS.AES.encrypt(random_numberWA, keyWA, { mode: CryptoJS.mode.ECB, padding: CryptoJS.pad.NoPadding });

// Encrypted data as WordArray
var encryptedWA = encryptedCP.ciphertext;

// Conversion to array
var encryptedBA = hexToBytes(CryptoJS.enc.Hex.stringify(encryptedWA));

// Utilize encryptedBA 
// ...

// Helper function from https://stackoverflow.com/a/34356351/9014097
function hexToBytes(hex) {
    for (var bytes = [], c = 0; c < hex.length; c += 2)
        bytes.push(parseInt(hex.substr(c, 2), 16));
    return bytes;
}

function bytesToHex(bytes) {
    for (var hex = [], i = 0; i < bytes.length; i++) {
        var current = bytes[i] < 0 ? bytes[i] + 256 : bytes[i];
        hex.push((current >>> 4).toString(16));
        hex.push((current & 0xF).toString(16));
    }
    return hex.join("");
}

To verify the result, please visit this link.

Answer 2

When using CryptoJS for AES encryption, there are several important considerations to keep in mind:

In the provided code snippet, keys and data intended for encryption (random_number) are explicitly designated as arrays. However, CryptoJS utilizes WordArray objects, necessitating a conversion. This can be achieved by easily converting WordArray objects into arrays through hexadecimal strings and vice versa using the provided functions and the CryptoJS Encoders. Alternatively, direct conversion can also be carried out using these functions.
Since the arrays contain arbitrary byte sequences (often not corresponding to readable characters), only suitable encodings such as Base64 or hexadecimal should be used. While it's unclear whether the methods bytesToString and stringToBytes pose any issues as they were not included in the excerpt, CryptoJS enables passing data as either a string or a WordArray, with the latter being employed subsequently.
Notably, if the second parameter in CryptoJS.AES.encrypt is passed as a string, it serves as a passphrase that generates the actual key via a defined algorithm, detailed here. Conversely, when this parameter is interpreted as a key (as evident in the reference code), it must be presented as a WordArray.
The chosen method for encryption is AES/ECB/NoPadding, as specified in the associated Medium article. The absence of padding is permissible due to the encrypted data's length aligning with integer multiples of the AES block size (16 bytes). Should this not hold true, padding would be obligatory.
Following encryption, the output comprises a CipherParams object whereby the encrypted data appears as a WordArray, outlined here.

For successful encryption implementation, the following steps need to be followed:

var CryptoJS = require("crypto-js");

// Key and random number as arrays, e.g.:
var random_numberBA = [0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f];
var keyBA = [0x01, 0x23, 0x45, 0x67, 0x89, 0x01, 0x22, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 0x89, 0x90, 0x02];

// Conversion to WordArrays
var random_numberWA = CryptoJS.enc.Hex.parse(bytesToHex(random_numberBA));
var keyWA = CryptoJS.enc.Hex.parse(bytesToHex(keyBA));

// Encryption
// - random_number as WordArray
// - Key as WordArray
// - ECB-Mode (default: CBC), No-Padding (default: Pkcs7-Padding)
var encryptedCP = CryptoJS.AES.encrypt(random_numberWA, keyWA, { mode: CryptoJS.mode.ECB, padding: CryptoJS.pad.NoPadding });

// Encrypted data as WordArray
var encryptedWA = encryptedCP.ciphertext;

// Conversion to array
var encryptedBA = hexToBytes(CryptoJS.enc.Hex.stringify(encryptedWA));

// Utilize encryptedBA 
// ...

// Helper function from https://stackoverflow.com/a/34356351/9014097
function hexToBytes(hex) {
    for (var bytes = [], c = 0; c < hex.length; c += 2)
        bytes.push(parseInt(hex.substr(c, 2), 16));
    return bytes;
}

function bytesToHex(bytes) {
    for (var hex = [], i = 0; i < bytes.length; i++) {
        var current = bytes[i] < 0 ? bytes[i] + 256 : bytes[i];
        hex.push((current >>> 4).toString(16));
        hex.push((current & 0xF).toString(16));
    }
    return hex.join("");
}

To verify the result, please visit this link.

Secure a byte array in JavaScript by utilizing the crypto js AES ECB algorithm

Answer №1

Similar questions

Ways to store the output of a <script src> tag into a variable

Unable to create a flawless circle using Canvas

Requesting the user to repeatedly input their birth year until it is less than the current year

The JQuery Ajax call returned with a status of 0 and an empty ResponseText

Script designed to track modifications on a specific webpage

Converting JSON object to a string

What are the steps to utilize fullcalendar events as variables in your code?

Java function to determine if each piece is on a different diagonal

d3.on event firing prior to mouseover event

Is there a beginner's pack or trial version available for utilizing TypeScript with IBM Cloud Functions / OpenWhisk?

Determining the selected section in Swift: A guide

Node.js is having trouble locating a module that has been installed

Attempting to display the contents of an array by iterating through it with a loop in a Angular JS using Javascript

What steps should I take to generate a stylized date input in javascript?

Is it possible to modify the background-color of a minified gallery using CSS in jQuery?

What are the steps to setting up an intelligent LAN or corporate npm registry for storing node.js packages?

To reveal truncated words one at a time for each item, simply hover your mouse over the text field to see the complete text appear

Having difficulty with the javascript click() function in an html document

Issue with Google Script not initializing in a second form

Fetching data using ajax and then appending it to the webpage