A strategy is described for associating an InternalsVisibleTo (IVT) attribute with a non-public resource of a first assembly. The IVT attribute names a second assembly. By virtue of the IVT attribute, during runtime, the non-public resource in the first assembly is made visible to the second assembly. In addition to naming the second assembly, the IVT attribute can include a number of optional arguments, such as arguments which specify the version, culture, and public key token associated with the second assembly.