encriptar.js

const encriptar = async (contraseña, textoPlano) => {
  const encoder = new TextEncoder();
  const sal = window.crypto.getRandomValues(new Uint8Array(16));
  const vectorInicializacion = window.crypto.getRandomValues(new Uint8Array(16));
  const bufferTextoPlano = encoder.encode(textoPlano);
  const clave = await derivacionDeClaveBasadaEnContraseña(contraseña, sal, 100000, 256, 'SHA-256');
  const encrypted = await window.crypto.subtle.encrypt(
    { name: "AES-CBC", iv: vectorInicializacion },
    clave,
    bufferTextoPlano
  );
  return bufferABase64([
    ...sal,
    ...vectorInicializacion,
    ...new Uint8Array(encrypted)
  ]);
};