The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

Organic–inorganic hybrid perovskite materials are attracting great interest for their applications in photovoltaics where they have demonstrated excellent efficiency. Here, Dou et al. demonstrate room temperature, solution-processed hybrid perovskite photodetectors with fast response and high detectivity.

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Solution-processed hybrid perovskite photodetectors with high detectivity

This review highlights the recent progress which has been made towards improved single-photon detector technologies and the impact these developments will have on quantum optics and quantum information science.

Single-photon detectors for optical quantum information applications

Chaos is good, if you are looking to send encrypted information across a broadband optical network. The idea that the transmission of light-based signals embedded in chaos can provide privacy in data transmission has been demonstrated over short distances in the laboratory. Now it has been shown to work for real, across a commercial fibre-optic channel in the metropolitan area network of Athens, Greece. The results show that the technology is robust to perturbations and channel disturbances unavoidable under real-world conditions. Chaotic signals have been proposed as broadband information carriers with the potential of providing a high level of robustness and privacy in data transmission1,2. Laboratory demonstrations of chaos-based optical communications have already shown the potential of this technology3,4,5, but a field experiment using commercial optical networks has not been undertaken so far. Here we demonstrate high-speed long-distance communication based on chaos synchronization over a commercial fibre-optic channel. An optical carrier wave generated by a chaotic laser is used to encode a message for transmission over 120 km of optical fibre in the metropolitan area network of Athens, Greece. The message is decoded using an appropriate second laser which, by synchronizing with the chaotic carrier, allows for the separation of the carrier and the message. Transmission rates in the gigabit per second range are achieved, with corresponding bit-error rates below 10-7. The system uses matched pairs of semiconductor lasers as chaotic emitters and receivers, and off-the-shelf fibre-optic telecommunication components. Our results show that information can be transmitted at high bit rates using deterministic chaos in a manner that is robust to perturbations and channel disturbances unavoidable under real-world conditions.

/pdf/chaos-based-communications-at-high-bit-rates-using-2z2lxtwks1.pdf

Chaos-based communications at high bit rates using commercial fibre-optic links

Squeezed states of the electromagnetic field have been generated by nondegenerate four-wave mixing due to Na atoms in an optical cavity. The optical noise in the cavity, comprised of primarily vacuum fluctuations and a small component of spontaneous emission from the pumped Na atoms, is amplified in one quadrature of the optical field and deamplified in the other quadrature. These quadrature components are measured with a balanced homodyne detector. The total noise level in the deamplified quadrature drops below the vacuum noise level.

Observation of squeezed states generated by four-wave mixing in an optical cavity

Photonic Instrumentation

This work performs numerical and experimental studies of coupled mode dynamics for monolithic semiconductor ring lasers. This study presents numerical analysis and experimental results of the different operating regimes, namely: bidirectional CW, bidirectional with harmonic oscillations of the mode intensities, and unidirectional.

Coupled-mode equations for monolithic semiconductor ring lasers: numerical simulations and experimental results

Using a laser diode as an echo detector of the optical reflection from a wafer surface, we demonstrate a very compact and extremely simple optical probe capable of measuring the curvature radius of a wafer, inside an MOCVD chamber, on the range from a few meters to about 10 km.

In-situ Measurement of Wafer Camber by a Laser-Feedback Detector

Self-mixing interferometry (SMI) is a new scheme of interferometry having several advantages compared to standard configurations: it can work with no optical part external to the laser, is self-aligned, is immune to external stray light, and can measure also on target with diffusing surfaces. In this paper, an overview of the several measurements already demonstrated with self-mixing is presented, with application tthe measurements of kinematic quantities (displacement, vibration. etc.) as well physical (linewidth, alfa factor, etc.)

A Universal Yardstick for Optical Measurements

In high-accuracy interferometric measurements, once the main sources of error (misalignement, refractive index fluctuation) are removed or compensated for, residual errors due to field curvature and to the statistical nature of the scattered field, typical of mirrorless self-mixing interferometry (SMI), persist. Field curvature (systematic) error can be compensated for from the knowledge of the mean phase space derivative dPhi/dz; the (random) error due speckle-pattern of the scattered field can be tamed by exploiting second order statistics of intensity and phase conditioned to intensity. Starting from knowledge of speckle pattern statistics we derive intra-speckle phase errors using the bivariate conditional probability, finding that the noise-equivalent-displacement (NED) for small displacement delta is proportional to the ratio of delta to speckle longitudinal size sl. Than we extend the analysis to inter-speckle displacements (delta>sl) and, after deriving speckle systematic and random errors, show that operation up to meters on a diffusing surface target is possible with a small (≈lambda) error. Results are of general validity for any configuration of interferometry, even if discussed in a SMI context.

http://ieeexplore.ieee.org/iel7/6971895/6984913/06985113.pdf

Silvano Donati

Papers

Photonic Instrumentation

Coupled-mode equations for monolithic semiconductor ring lasers: numerical simulations and experimental results

In-situ Measurement of Wafer Camber by a Laser-Feedback Detector

A Universal Yardstick for Optical Measurements

Ultimate error sources in self-mixing interferometry