The IRS and its Security Summit partners today called on tax professionals and taxpayers to use the free, multi-factor authentication feature being offered on tax preparation software products. Already, nearly two dozen tax practitioner firms have reported data thefts to the IRS this year. Use of the multi-factor authentication feature is a free and easy way to protect clients and practitioners' offices from data thefts. Tax software providers also offer free multi-factor authentication protections on their Do-It-Yourself products for taxpayers.