Are there any major flaws with this seed phrase encryption approach?

I would like to add security to my existing wallet seed phrase storage. We’re not trying to make it absolutely safe. I just want to make it more difficult for someone to access my funds if they find my seed phrase storage.

I’m considering this approach:

1. Convert seed phrase to entropy
2. Encrypt entropy with a password
3. Convert the encrypted entropy into a new (longer) seed phrase.
4. Save encrypted seed phrase

Then, if necessary, reverse the operation to get your first seed phrase.

I’ve included the JS code to demonstrate it below. I used AES CEB without the initial vector and empty key salt so that it is not needed for decryption.

I suspect there is a major flaw in my approach or code.

I understand that using a password to increase the security of my Seed Phrase Storage increases the likelihood that I will not be able to access my Seed Phrase Storage if I forget my password.

import crypto from "crypto";
import bip39 from "bip39-light";

const algorithm = "aes-256-ecb";
const initialVector = null;
const keySize = 32;
const keySalt = "";

const inputPassword = ""; // password goes here
const inputMnemonic = ""; // 12 word seed phrase goes here

// encrypt 12-word input mnemonic to 24-word mnemonic
const encryptedMnemonic = encryptMnemonic(inputMnemonic, inputPassword);

// decrypt 24-word mnemonic back to 12-word mnemonic
const decryptedMnemonic = decryptMnemonic(encryptedMnemonic, inputPassword);

console.log({ inputMnemonic, encryptedMnemonic, decryptedMnemonic });

function encryptMnemonic(mnemonic, password) {
  const key = crypto.scryptSync(password, keySalt, keySize);

  const entropy = bip39.mnemonicToEntropy(mnemonic);
    
  const cipher = crypto.createCipheriv(algorithm, key, initialVector);
  
  let encryptedEntropy = cipher.update(entropy, "hex", "hex");
  encryptedEntropy += cipher.final("hex");
  
  let encryptedMnemonic = bip39.entropyToMnemonic(encryptedEntropy);
  return encryptedMnemonic;
}

function decryptMnemonic(mnemonic, password) {
  const key = crypto.scryptSync(password, keySalt, keySize);

  let encryptedEntropy = bip39.mnemonicToEntropy(mnemonic);
  
  const decipher = crypto.createDecipheriv(algorithm, key, initialVector);
  
  let decryptedEntropy = decipher.update(encryptedEntropy, "hex", "hex");
  decryptedEntropy += decipher.final("hex");
    
  let decryptedMnemonic = bip39.entropyToMnemonic(decryptedEntropy);
  return decryptedMnemonic;
}