We live in an interconnected world where information is becoming the currency of the realm. According to UC Berkeley School of Information we produce more than 550 000 Terabytes1 of data each year and our current adversaries are leveraging this wealth of information into concrete operational advantages better then we can. By shying away from traditional operational security principles and moving to what could be described as open source warfare, they can adapt more quickly to a given situation. A striking example of open source can be found in the Iraqi insurgency. It took only 12 months to reach (and surpass) capabilities for the deployment of the full spectrum of IEDs in Iraq that took over 30 years for the IRA to achieve under more rigorous operational security (OPSEC) conditions in Ulster2. Based on the fact that open source concepts are currently being used by the computer programming community, by many different business sectors and by certain segments of the enemy3 fighting in the contemporary operational environment, we must ask ourselves if the current military paradigm of operational security is still relevant. This paper will propose that a concept of open source warfare will be far more effective in supporting a campaign design methodology during complex emergencies as opposed to the traditional compartmentalized approach favoured in today's military planning process. First of all, we will look where this concept can be employed and why it would work. Having identified where open source can be useful for the military, we will turn our attention to the need of changing our understanding of OPSEC. Finally, we will propose an open source planning model which will allow us to better leverage information during campaign design and execution.