Leidos [LDOS] on Sept. 12 won a potential $684 million contract from the General Services Administration (GSA) to support the Department of Homeland Security’s secure data network used to share classified information across government agencies involved in homeland security missions.

Leidos unseated Northrop Grumman [NOC], which won a contract in 2004 to develop and implement the Homeland Security Data Network (HSDN). In 2011 Northrop Grumman won another contract, potentially worth $1.1 billion, to upgrade and continue operating the HSDN.

Under the new Secure Enterprise Network Systems, Services and Support (SENS3) task order, awarded by GSA’s Federal Systems Integration and Management Center on behalf of DHS, Leidos will provide operations and maintenance, security, optimization, enhancement, design, engineering, architecture, integration, configuration, testing, and expansion of the HSDN and the Classified Local Area Network.

The SENS3 task order has a base period and five one-year options. The award was made under the GSA Alliant contract vehicle.

Leidos said that its work will include providing continual service improvement throughout the life of the task order.

“We’re proud that DHS has entrusted Leidos to operate and modernize its enterprise systems to support information sharing and intelligence missions across all DHS components, including federal, state, local, and tribal partners,” Angie Heise, Leidos Group president, said in a statement. She said Leidos will “streamline information sharing across all DHS stakeholders.”