On Dec. 23, the last thing holiday shoppers at Target wanted tobe thinking about was having their credit-card informationcompromised. But that was one luxury no one on hand couldafford.

“We don't know yet,” one harried store manager in Staten Islandpainfully admitted to one especially persistent elderly womandemanding answers about what data thieves now knew. Was she safe?Could she continue to shop? Should she? How badly had the retailgiant's consumer database been compromised? No one could say forcertain.

Target's data breach, involving the theft of at least 40 millioncredit and debit card records and personal information of 70million customers, dominated headlines after it was publiclyrevealed in late December 2013, driving home the need for betterprotections against the growing specter of cyber crime. But if theTarget incident was unusually large in scope, it was by no meansunique: The Identity Theft Resource Center, which has tracked databreaches since 2005, reported 619 publicly disclosed breaches in2013—a 30% increase over 2012.