The faces of 120 million people — more than one-third of the people who live in the United States — are in searchable photo databases assembled by officials in all fifty states for the purpose of preventing driver’s-license fraud. These databases, however, are increasingly being used by law enforcement agencies to identify suspects, accomplices, and even innocent bystanders as part of a wide range of criminal investigations. These facial databases, which have rapidly grown in recent years, are generally operated with few if any legal safeguards beyond the requirement that searches are conducted for “law enforcement purposes.”