Unbreakable Keys from Random Noise

Romain Alléaume

Hadi Ahmadi, Reihaneh Safavi–Naini

Stamatios V. Kartalopoulos

Quantum cryptographic systems use quantum mechanical concepts that are based on qubit superposition of states, and on the no cloning or no copying theorem to establish unbreakable cipher keys. Using optical communications the most commonly quantum mechanical property used is the polarization state of photon. However, in most quantum cryptographic algorithms a random polarization state is required. In this case, the random number generator should not be publically known, and it should be preferably reproducible. A naturally reproducible RNG can be produced using chaos functions. In this paper we review a quantum key distribution algorithm and chaos functions as RNGs. We then describe how chaos functions can be used in quantum key establishment and also a method that requires substantially fewer bits in the stream to establish the key and also a faster method.

Deng-Gao Lai, Jie‐Qiao Liao, Adam Miranowicz +1 more

Entanglement of light and multiple vibrations is a key resource for multichannel quantum information processing and memory. However, entanglement generation is generally suppressed, or even fully destroyed, by the dark-mode (DM) effect induced by the coupling of multiple degenerate or near-degenerate vibrational modes to a common optical mode. Here we propose how to generate optomechanical entanglement via DM breaking induced by synthetic magnetism. We find that at nonzero temperature, light and vibrations are separable in the DM-unbreaking regime but entangled in the DM-breaking regime. Remarkably, the threshold thermal phonon number for preserving entanglement in our simulations has been observed to be up to 3 orders of magnitude stronger than that in the DM-unbreaking regime. The application of the DM-breaking mechanism to optomechanical networks can make noise-tolerant entanglement networks feasible. These results are quite general and can initiate advances in quantum resources with immunity against both dark modes and thermal noise.

Rade Vuckovac

Ram Soorat, K. Madhuri, Ashok Vudayagiri

One key requirement for many cryptograhic schemes is the generation of random numbers.Sequences of random numbers are used at several stages of a standard cryptographic protocol.One simple example is a Vernam cipher, where a string of random numbers is added to message string to generate encrypted code.C = M ⊕ K.It has been mathematically shown that this simple scheme is unbreakable if key K is as long as M and is used only once.The security of a cryptosystem shall not be based on keeping the algorithm secret but solely on keeping the key secret.The security of a random number generator (RNG) is related to the difficulty of predicting its future sequence values from past values.The quality and unpredictability of secret data is critical to securing communication by modern cryptographic techniques.The generation of such data for cryptographic purposes typically requires an unpredictable physical source of random data.We studied a chaotic circuit which consisted of an inductor, capacitance, diode and thus used for the BB84 protocol.We have studied both pseudo random and true random number generators and evaluated them through various tests like frequency, correlation, NIST etc.