In this book, the authors present a method for secure quantum key distribution based on a special Deutsch–Jozsa algorithm using Greenberger–Horne–Zeilinger states. Quantum mechanics is successful in explaining and predicting many physical phenomena, and there is therefore good reason to believe in its correctness. Among the interesting applications of quantum principles is their marriage with information theory, which leads to the concept of quantum computing. Furthermore, the authors discuss how the Bernstein—Vazirani algorithm can be used for quantum communication with the inclusion of error correction and over a noisy environment. Finally, the authors discuss other potential algorithms for quantum communication and for solving mathematical problems such as the parity problem and roots of a polynomial.