StrikeForce Technologies is accusing three firms of encroaching on its technology for protecting customers of financial institutions from online identity theft.

In a lawsuit filed Thursday in U.S. District Court in Wilmington, the mobile technology company charged authentication provider PhoneFactor, Fiserv (FISV) and First Midwest Bancorp (FMBI) with infringing intellectual property that underlies StrikeForce's system for regulating electronic access to bank accounts, social networks and other online services.

StrikeForce alleges that PhoneFactor has been selling a system for authenticating accounts that copies critical features of a patent held by StrikeForce.

Both Fiserv, which teamed with PhoneFactor nearly three years ago to pair PhoneFactor's technology with Fiserv's software for banks, and First Midwest have violated the patent through their use of PhoneFactor's technology, according to StrikeForce.

Mark Kay, StrikeForce's chief executive, vowed in a press release "to protect this critical StrikeForce asset, which is definitely increasing in importance with consistently troubling news about cyberattacks and cyber thefts."

Spokespeople for PhoneFactor, Fiserv and First Midwest Bancorp did not respond immediately to a request for comment.

The patent, which StrikeForce obtained in 2011, encompasses several technologies that support a system of securing networks. The system relies on a mix of hard tokens that people carry and digital tokens that are installed in mobile devices.

StrikeForce touts the system as a superior method for authenticating access than either fixed passwords or the plastic token-based systems that many financial institutions currently use.

The lawsuit asks the court to stop PhoneFactor, Fiserv and First Midwest from using systems that allegedly draw on StrikeForce's technology or to license the technology from StrikeForce and pay the company unspecified monetary damages.