Sometimes it seems as if every day ending in “y” brings news of another massive security breach exposing Social Security numbers and other personal information for millions of people. Millions? Oops. Make that billions. We were still figuring out how to protect ourselves after the failure of the Equifax credit reporting agency to safeguard financial information affecting as many as 145.5 million people. And now comes news that a 2013 breach at Yahoo was three times larger than originally announced, affecting 3 billion accounts. To paraphrase Everett Dirksen’s famous quip about federal spending, a billion here, a billion there and pretty soon you’re talking about real money. As in public expenses for credit monitoring and credit freezes, not to mention any losses from identify theft stemming from the failure of big data companies to secure themselves against hackers.