This document summarises discussions held at the second annual event of the OECD Global Forum on Digital Security for Prosperity. The event, held on 14-15 November 2019 in London, brought together 160 experts and 30 speakers from government, business, civil society, the technical community and academia to discuss how to encourage digital security innovation. Participants explored the roles that different stakeholders can play in stimulating digital security innovation, including how governments can support it for example by implementing tax incentives, acting as an early customer for innovative products, and enacting flexible and outcome-based regulation. A digital security innovation ecosystem is the most important component of a strategic approach, as it brings together different stakeholder groups in a dedicated location. Participants discussed how different ecosystems can learn from one another through international co-operation and considered how governments can encourage digital security by design in innovation more generally.