How do i decrypt after wards in npm - node.js

Question

I have the example from nodejs.org for the file encryption
const fs = require('fs');
const algorithm = 'aes-192-cbc';
const password = 'Password used to generate key';
// Use the async `crypto.scrypt()` instead.
const key = crypto.scryptSync(password, 'salt', 24);
// Use `crypto.randomBytes()` to generate a random iv instead of the static iv
// shown here.
const iv = Buffer.alloc(16, 0); // Initialization vector.
const cipher = crypto.createCipheriv(algorithm, key, iv);
const input = fs.createReadStream('test.js');
const output = fs.createWriteStream('test.enc');
input.pipe(cipher).pipe(output);
}
How do i do the oposite and get test.enc to test.js using the same key?
Thanks in advance

Answer 1

You can use a similar process to decrypt the file that you have encrypted using the above code.
We'll write the decrypted file to "test-decoded.js" so we don't end up overwriting our original file.
I'd also point out that you should ideally populate the IV with a random value and store this with the encrypted data, though if you're just testing it doesn't really matter too much!
const fs = require('fs');
const crypto = require("crypto");
const algorithm = 'aes-192-cbc';
const password = 'Password used to generate key';
const key = crypto.scryptSync(password, 'salt', 24);
const iv = Buffer.alloc(16, 0); // Initialization vector.
const decryptInput = fs.createReadStream('test.enc');
const decryptOutput = fs.createWriteStream('test-decoded.js');
const decipher = crypto.createDecipheriv(algorithm, key, iv);
decryptInput.pipe(decipher).pipe(decryptOutput);