code: @Override
      public byte[] load(String key) throws IOException {
          try {
              File f = getFileFor(key);
              if (!f.exists()) return null;
  
              Cipher sym = Cipher.getInstance("AES");
              sym.init(Cipher.DECRYPT_MODE, masterKey);
              try (
                      FileInputStream fis = new FileInputStream(f);
                      CipherInputStream cis = new CipherInputStream(fis, sym)
              ) {
                  byte[] bytes = IOUtils.toByteArray(cis);
                  return verifyMagic(bytes);
              }
          } catch (GeneralSecurityException e) {
              throw new IOException("Failed to persist the key: " + key, e);
          }
      }
docs: Reverse operation of {@link #store(String, byte[])}
  
  @return null the data has not been previously persisted.