The IRS is teaming up with tax preparation firms to find ways to strengthen the security of its filing system after a series of cyber attacks led to criminals stealing the personal information of thousands of U.S. taxpayers, according to the Wall Street Journal. Participants include retail non-CPA tax services such as Intuit, H&R Block, Jackson Hewitt, Liberty Tax, and a few others, said the Journal. Together, it is believed they will focus on stronger taxpayer identity validation, as well as data sharing to help combat future fraud, said the Journal.