Cryptography Apocalypse

7Quantum Cryptography

Chapter 6 covered traditional, binary cryptography that is resistant to known quantum attacks. This chapter covers quantum-based cryptography, cryptography that exists and operates on quantum devices using quantum properties. Quantum-based cryptography is also inherently resistant to known quantum attacks, as well as attacks from traditional binary computers. Binary cryptography is an acceptable defense in a post-quantum world where not enough widely available, cheap quantum computing and networking devices exist. But quantum-based cryptography is theoretically much safer to all known attacks and will likely be the cryptographic choice for long-term security. In this chapter, we will cover the main types of quantum cryptography, including random number generators (RNGs), hashes, key distribution, and digital signatures. Chapter 8 will explore quantum networking.

Inherent in all of these quantum cryptography implementations are all the popular quantum mechanics properties. However, four particular quantum properties show up again and again as being central to how quantum cryptography provides its protective superpowers: superposition, entanglement, the observer effect, and the no-cloning theorem. Superposition gives more possible choices than what a binary digit can offer. Entanglement often provides the way for the involved cryptographic secrets to be transmitted between the authorized parties. The observer effect and the no-cloning theorem make it harder ...