Subhash Kak’s research spans the fields of information theory, cryptography, neural networks, and quantum information. He has developed new families of random sequences for applications to computing, cryptography and network security. He is the inventor of instantaneously trained neural networks for which a variety of artificial intelligence applications have been found. He has argued that brain function is associated with three kinds of language: associative, reorganizational, and quantum. His work on quantum information includes the only all-quantum protocol for public-key cryptography.
He has also done research on archaeoastronomy and history of science, and he is the author of twenty books.