Shortest and simplest string encryption / decryption with AES-256 in Node.JS

Copy and paste the following code in a .js file, then run it.

// Libraries
const crypto = require('crypto');

// Constants
const OUTPUT_FORMAT = "hex";
const ALGORITHM = "aes256";
const KEY = "012345ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const IV = "ABCDEF0123456789";

// Implementations
function encrypt(message) {
    let cipher = crypto.createCipheriv(
        ALGORITHM, 
        Buffer.from(KEY), 
        Buffer.from(IV)
    );
    return (Buffer.concat([
        cipher.update(message), 
        cipher.final()
    ])).toString(OUTPUT_FORMAT);
}

function decrypt(message) {
    let decipher = crypto.createDecipheriv(
        ALGORITHM, 
        Buffer.from(KEY), 
        Buffer.from(IV)
    );
    return (Buffer.concat([
        decipher.update(Buffer.from(message, OUTPUT_FORMAT)),
        decipher.final()
    ])).toString('utf8');
}

// Program
console.log(encrypt("Hello"));
console.log(decrypt(encrypt("Hello")));

Sample output:

c5c79e5679cb7e3fef8412c2564f8427
Hello