Introduction to Classical Cryptography -- Contemporary Quantum Key Distribution Techniques -- The Y-00 Protocol -- Multi-stage Multi-Photon Techniques in Cryptography -- Variations of Multi-Photon Protocols -- Multi-stage Multi-Photon Techniques in Wireless Communication -- Cryptographic strength of Multi-Photon Techniques -- Intrusion Detection System using the Polarization Channel -- Secure Key Transfer Using the Polarization Channel. .

This book explores alternative ways of accomplishing secure information transfer with incoherent multi-photon pulses in contrast to conventional Quantum Key Distribution techniques. Most of the techniques presented in this book do not need conventional encryption. Furthermore, the book presents a technique whereby any symmetric key can be securely transferred using the polarization channel of an optical fiber for conventional data encryption. The work presented in this book has largely been practically realized, albeit in a laboratory environment, to offer proof of concept rather than building a rugged instrument that can withstand the rigors of a commercial environment. .