Implementation using modern libraries

The issue names no repository files, entry points, or tests; start by inspecting the package API and current implementation to determine whether the proposed JavaScript encryption and decryption functions fit this project. The issue provides example code but no acceptance criteria, so the intended API, compatibility requirements, and tests for completion need to be clarified first.

For all those who are looking for a replacement for the following code:

import AES from 'crypto-js/aes.js';
import Utf8 from 'crypto-js/enc-utf8.js';

function encrypt(data, key) {
  return AES.encrypt(data, key).toString();
}

function decrypt(data, key) {
  return AES.decrypt(data, key).toString(Utf8);
}

const data = 'This is a secret message';
const password = '12345';

data === decrypt(encrypt(data, password), password);

Below is an implementation using modern libraries:

import { md5 } from '@noble/hashes/legacy.js';
import { cbc } from '@noble/ciphers/aes.js';
import { base64 } from '@scure/base'
import {
  abytes,
  bytesToUtf8,
  concatBytes,
  randomBytes,
  utf8ToBytes,
} from '@noble/hashes/utils.js';

export function evpBytesToKey(password, salt = new Uint8Array(0), keyLen = 32, ivLen = 16, count = 1) {
  abytes(password);
  abytes(salt, 0, 8);
  let derived = new Uint8Array(0);
  let block = new Uint8Array(0);

  while (derived.length < (keyLen + ivLen)) {
    block = md5(concatBytes(block, password, salt));
    for (let i = 1; i < count; i++) {
      block = md5(block);
    }
    derived = concatBytes(derived, block);
  }

  return {
    key: derived.slice(0, keyLen),
    iv: derived.slice(keyLen, keyLen + ivLen)
  };
}

export function encrypt(data, password) {
  const salt = randomBytes(8);
  const { key, iv } = evpBytesToKey(utf8ToBytes(password), salt, 32, 16);
  const encrypted = concatBytes(
    utf8ToBytes('Salted__'),
    salt,
    cbc(key, iv).encrypt(utf8ToBytes(data))
  );
  return base64.encode(encrypted);
}

export function decrypt(data, password) {
  const encrypted = base64.decode(data);
  const salt = encrypted.slice(8, 16);
  const { key, iv } = evpBytesToKey(utf8ToBytes(password), salt, 32, 16);
  return bytesToUtf8(cbc(key, iv).decrypt(encrypted.slice(16)));
}