National security is often synonymous with secrecy. But when it comes to software development, the U.S. defense and intelligence establishment can be surprisingly open. This week, the Defense Advanced Research Projects Agency — or DARPA, the research arm of the U.S. Defense department — published a list of all the open source computer science projects it has funded, including links to source code and academic papers that detail the code’s underlying concepts. Anyone is free to not only peruse the source code and add to it, but actually use it to build their own software — and that includes foreign governments. The belief is that because anyone can contribute to these projects, the quality of the code will only improve, making the software more useful to everyone. It’s an approach that has paid off in spades among web companies from Google and Facebook to Twitter and Square, and the government has now realized that it too can benefit from the open source ethos.