code: private static String toDigest(String input) {
          md.reset();
          try {
              md.update(input.getBytes("UTF-8"));
          } catch (UnsupportedEncodingException e) {
          }
          String result = com.ibm.ws.common.internal.encoder.Base64Coder.base64EncodeToString(md.digest());
          //String result = Base64.getEncoder().encodeToString(md.digest());  // java8 only
          return result;
      }
docs: store as digests to save space