How to use the @f5devcentral/f5-cloud-libs.cryptoUtil function in @f5devcentral/f5-cloud-libs

const fs = require('fs');
const util = require('util');
const path = require('path');
const stream = require('stream');

const q = require('q');

const Compute = require('@google-cloud/compute');
const Storage = require('@google-cloud/storage');

const CloudProvider = require('@f5devcentral/f5-cloud-libs').cloudProvider;
const AutoscaleInstance = require('@f5devcentral/f5-cloud-libs').autoscaleInstance;
const BigIp = require('@f5devcentral/f5-cloud-libs').bigIp;
const Logger = require('@f5devcentral/f5-cloud-libs').logger;
const cloudUtil = require('@f5devcentral/f5-cloud-libs').util;
const cryptoUtil = require('@f5devcentral/f5-cloud-libs').cryptoUtil;
const PubSub = require('../src/gcClients/pubSub');
const KEYS = require('@f5devcentral/f5-cloud-libs').sharedConstants.KEYS;

const CREDENTIALS_FILE = 'credentials/master';
const INSTANCES_FOLDER = 'instances/';
const PUBLIC_KEYS_FOLDER = 'public_keys/';
const BACKUP_FOLDER = 'backup/';

const JOIN_PREFIX = 'JOIN_';
const SYNC_COMPLETE_PREFIX = 'SYNC_COMPLETE_';

let bigIp;
let logger;

util.inherits(GceCloudProvider, CloudProvider);