esp crypto-js

3 min read 18-10-2024

Encrypting Your Data with ESP32 and CryptoJS: A Comprehensive Guide

The ESP32, a powerful and versatile microcontroller, is widely used in embedded systems. But what about security? Protecting sensitive data on your ESP32 is crucial. This article explores how you can use the widely-adopted CryptoJS library to implement secure encryption on your ESP32.

Why CryptoJS for ESP32?

CryptoJS is a JavaScript library specifically designed for cryptographic operations. While JavaScript is traditionally used for web development, the ESP32 can actually run JavaScript code thanks to the Espruino framework. This makes CryptoJS a perfect fit for implementing secure encryption on your ESP32.

The Basics of CryptoJS and Encryption

What is Encryption?

Encryption is the process of transforming data into an unreadable format (ciphertext) using an algorithm and a secret key. Only those with the correct key can decrypt the ciphertext and access the original data.

Why Use CryptoJS?

CryptoJS offers a comprehensive suite of cryptographic algorithms including:

AES (Advanced Encryption Standard): A widely used symmetric encryption algorithm.
DES (Data Encryption Standard): A legacy symmetric encryption algorithm, less secure than AES.
Triple DES (3DES): An enhancement to DES offering better security.
RSA: An asymmetric encryption algorithm used for key exchange and digital signatures.
SHA256: A secure hashing algorithm used for data integrity verification.

Key Concepts:

Symmetric Encryption: Uses the same key for both encryption and decryption.
Asymmetric Encryption: Uses a separate key for encryption and decryption.
Hashing: Creates a unique fingerprint (hash) of data, ensuring integrity and authenticity.

Encrypting Data with CryptoJS on ESP32

Let's see how we can encrypt data using AES-256 with CryptoJS on the ESP32.

1. Set Up the ESP32 with Espruino:

Flashing Espruino: Download the latest Espruino firmware from https://www.espruino.com/ and flash it onto your ESP32 using the Espruino Uploader.
Connecting: Establish a serial connection to your ESP32 using a USB cable.

2. Install CryptoJS:

Using the require function: This method directly imports the library:
```
var CryptoJS = require('crypto-js'); 
```
Installing via Espruino libraries: You can install CryptoJS from Espruino's library manager.

3. Implementing Encryption:

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

// Generate a secret key (256 bits)
var secretKey = CryptoJS.lib.WordArray.random(16); // 16 words = 256 bits

// Data to encrypt
var dataToEncrypt = "This is some sensitive data";

// Encrypt the data using AES-256 in CBC mode
var ciphertext = CryptoJS.AES.encrypt(dataToEncrypt, secretKey, {
    iv: CryptoJS.lib.WordArray.random(16), // 16-byte Initialization Vector
    mode: CryptoJS.mode.CBC
});

// Output the encrypted ciphertext
console.log("Encrypted data: " + ciphertext.toString());

4. Decrypting the Data:

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

// Retrieve the ciphertext
var ciphertext = "your encrypted data (e.g., U2FsdGVkX1...";

// Decrypt using the same key and IV
var decryptedData = CryptoJS.AES.decrypt(ciphertext, secretKey, {
    iv: CryptoJS.lib.WordArray.random(16), 
    mode: CryptoJS.mode.CBC
});

// Print the decrypted data
console.log("Decrypted data: " + decryptedData.toString(CryptoJS.enc.Utf8));

Important Considerations:

Key Management: Storing and managing the secret key securely is paramount. Never hardcode keys directly into your code. Consider secure storage solutions like EEPROM or external secure elements.
Initialization Vectors (IVs): Always use unique and random IVs for each encryption operation to enhance security.

Practical Applications of CryptoJS on ESP32

Protecting Sensitive Data: Securely store user credentials, API keys, or other sensitive data.
Communication Security: Encrypt data transmitted between your ESP32 and other devices over insecure channels.
Data Integrity: Ensure data integrity by hashing sensitive data using algorithms like SHA256.

Note: This article provides a simplified example. For more complex security scenarios, you might need to explore advanced cryptography concepts, such as key derivation and secure communication protocols.

Conclusion

CryptoJS offers a simple and efficient way to implement secure encryption on your ESP32. By leveraging its powerful cryptographic functions and understanding the core concepts of encryption, you can significantly enhance the security of your embedded systems.

This article was created based on information from https://www.espruino.com/ and https://cryptojs.org/.