Quantum Cryptography Without Switching

Quantum cryptography without switching.

We propose a new coherent state quantum key distribution protocol that eliminates the need to randomly switch between measurement bases. This protocol provides significantly higher secret key rates with increased bandwidths than previous schemes that only make single quadrature measurements. It also offers the further advantage of simplicity compared to all previous protocols which, to date, ha...

Quantum cryptography without a quantum channel

Quantum key distribution (QKD) proposals for quantum-mechanically secure communications include mechanisms that allow the detection of eavesdropping, but they require the previous use of a quantum channel to exchange the cryptographic key. We present a cryptographic protocol based on entanglement swapping and quantum dense coding that, making use of previous entanglement between the two parties...

Cryptography. Simple noise may stymie spies without quantum weirdness.

With the grand ambition of sending unbreakable coded messages, some physicists are using exotic tools—streams of individual photons and quantum mechanics—to shut out prying eyes. But a wire and a few resistors may convey a message as securely, says a physicist who has devised a simple and—he claims—uncrackable scheme. The idea shows that “classical” methods might compete with budding “quantum c...

Quantum Cryptography

Quantum cryptography

This is a chapter on quantum cryptography for the book “A Multidisciplinary Introduction to Information Security” to be published by CRC Press in 2011/2012. The chapter aims to introduce the topic to undergraduate-level and continuing-education students specializing in information and communication technology.