Banks and other financial firms are using technology to make sure data doesn’t fall into the wrong hands. The financial-services industry has been roiled this year by a string of data-security lapses involving tapes lost in transit, losses and theft of payment-card information, phishing attacks, and insider scams. The list of companies that have been stung reads like a Who’s Who of the financial-services industry: Ameritrade, Bank of America, Citigroup, City National Bank, Commerce Bancorp, PNC Financial Services, and Wachovia.