Sydney startup Cog Systems – which claims to build the world’s most secure IoT devices – has secured $3.5 million in funding from Atlassian cofounder Mike Cannon-Brookes’ venture capital firm, Grok Ventures, and Australian tech venture fund rampersand.

The investment is one of Grog Ventures’ first, and Cannon-Brookes said Cog Systems was building pioneering software that would change the industry.

“Security of connected devices is increasingly an important challenge to solve. The team at Cog are world-class with deep expertise in solving complex problems,” he said.

Cog Systems says it will use the funds to expand its D4 secure platform from mobile phones to other internet-connected devices, including the estimated eight billion IoT devices that are currently at risk, and to add a San Francisco office to its current locations in Sydney and Chicago.

The company already has one commercial product: a highly secure mobile phone, a version of the HTC One A9 secured with its D4 platform, which it has already supplied to the US government and several Fortune 500 companies.

It says the US Department of Defense acquired the first round of commercially available devices for its internal use.

Cog Systems’ technology has its origins in the OKL4 microkernel for smartphones, developed by Australian government research organisation NICTA (now Data61 and part of the CSIRO). Cog Systems’ cofounder and CEO Daniel Potts was a member of the team that developed OKL4.

NICTA set up OK Labs as a commercial entity to develop and market OK4L in August 2006 and spun it out as a commercial entity in April 2007.

By January 2012 OKL4 had been embedded in more than 1.5 billion smartphones from almost every major manufacturer. NICTA sold the company to US based General Dynamics in September 2012, and General Dynamics now claims to be the global leader in virtualisation software for securing wireless communications, applications, and content, with OKL4 now deployed in more than two billion devices.

Potts moved to General Dynamics at the time of the acquisition and left in March 2015. He said Cog Systems had started by securing the most personal connected device – the smartphone prior to moving to securing a much wider range of devices, from automotive to home automation.”

“By steering the security architecture from monolithic to modular, we have brought proactive security to governments and the enterprise without compromising the user experience,” he said.