This code contains a Darwin version of CDSA along with many other security libraries. Information about CDSA may be obtained from the OpenGroup web site at: http://www.opengroup.org/pubs/catalog/c914.htm Further information regarding the security of the MacOSX product is available at: http://www.apple.com/support/security/ Developers wishing to know more about developing their products in a manner consistent with MacOS security should view: http://developer.apple.com/macos/security.html To build this project in a Darwin environment (as opposed to building in-house at Apple), use the Darwin buildstyle. If you're building with Xcode, select "Darwin" from the "Active Build Style" popup. If you're building from the command line, specify the build style like so: % xcodebuild -buildstyle Darwin install This build style is necessitated by the fact that the CSP built at (and shipped by) Apple includes some algorithms which are proprietary to Apple; the source code for these algorithms is not open source. Selecting the Darwin build style allows the Security project (and also the CSP, in the libsecurity_apple_csp project, which also must be built with the Darwin build style) to be built from the Darwin open source tree without requiring the source for these algorithms.