What do Sony Corp.’s PlayStation Network, Zappos.com, Hannaford Brother Co.’s grocery stores, and South Carolina’s Department of Revenue all have in common?

Each has been the victim of a serious data breach. Data breaches can occur in a variety of ways, some by accident, some motivated by profit or political belief, and some simply for the sport of it. A breach can result from a malicious attack designed to destroy or disable a network or to steal private, competitive or proprietary information; from a disgruntled employee out for revenge; from the negligence of a vendor handling data; or from a laptop or thumb drive being left accidentally in a cab or airport. Paper documents also are involved in a significant number of data breaches.