Encrypt and Decrypt using AES-256-CBC in node environment

encryption.js

import { randomBytes, createCipheriv, createDecipheriv } from 'node:crypto'

// Secret key and IV
const key = randomBytes(32) // 32 bytes for AES-256
const iv = randomBytes(16)  // 16 bytes IV

// Encrypt function
function encrypt(text) {
    // Create a cipher instance using the AES-256-CBC algorithm with the declared key, and iv
    const cipher = createCipheriv('aes-256-cbc', key, iv)
    // Encrypt the text
    const encrypted = Buffer.concat([cipher.update(text), cipher.final()])
    // Return the encrypted iv and text and convert it to hex string, so you can read it
    return { iv: iv.toString('hex'), encryptedData: encrypted.toString('hex') }
}

// Decrypt function
function decrypt(encryptedText) {
    // Convert the hexadecimal IV back into a buffer
    const ivBuffer = Buffer.from(encryptedText.iv, 'hex')
    // Convert the hexadecimal encrypted data back into a buffer
    const encryptedData = Buffer.from(encryptedText.encryptedData, 'hex')
    // Create a decipher instance using the same algorithm and key as the encryption, and the IV from the encrypted text
    const decipher = createDecipheriv('aes-256-cbc', key, ivBuffer)
    // Decrypt the text, finalize, and return it
    return Buffer.concat([decipher.update(encryptedData), decipher.final()]).toString()
}

// Example usage
const text = "Hello World!"

const encrypted = encrypt(text)
console.log('Encrypted:', encrypted)

const decrypted = decrypt(encrypted)
console.log('Decrypted:', decrypted)


// Important notes and points:
// 1. Make sure that the key and IV are securely generated and stored. Never hard code it in a real application.
// 2. Add error handling for production code.