I am performing the MAC OS receipt validation with the steps mentioned in the Apples official document. The first step says to add ASN1c tool generated files to the Xcode Project. But even after adding the frameworks and other Linker flags mentioned in the thread "Mac App Store Receipt Validation Code?" in this forum I am still getting lot of errors. Has anyone successfully compiled the added ASN files in Xcode (The added files are of .c extension). If so can anyone point out what are the steps performed?