While many technologies that make use of computing haveproven themselves extremely reliable and trustworthycomputers helped transport people to the moon and back,they control critical aircraft systems for millions of flightsevery year, and they move trillions of dollars around theglobe dailythey generally haven’t reached the point wherepeople are willing to entrust them with their lives, implicitlyor explicitly. Many people are reluctant to entrust today’scomputer systems with their personal information, such asfinancial and medical records, because they are increasinglyconcerned about the security and reliability of these systems,which they view as posing significant societal risk. Ifcomputing is to become truly ubiquitous-and fulfill theimmense promise of technology-we will have to make thecomputing ecosystem sufficiently trustworthy that peopledon’t worry about its fallibility or unreliability the way theydo today.