With sales of bogus prescription drugs amounting to tens of billions of dollars worldwide, imperiling public health systems and pharmaceutical supply chains, counterfeit medications are an enormous threat — but the solution to that threat could be smaller than the period at the end of this sentence. And it could be designed here in Pittsburgh. Oh, and you’d have to swallow it. Researchers at Carnegie Mellon University are working on a radio-frequency tagging system that could be embedded into pills and encrypted with codes that would guarantee the provenance and authenticity of the medication. “Think of a grain of salt....