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」

I. Introduction and Scope 231A. Definitions of Atomic Electron Affinities 233B. Definitions of Molecular Electron Affinities 233II. Experimental Photoelectron Electron Affinities 235A. Historical Background 235B. The Photoeffect 236C. Experimental Methods 237D. Time-of-Flight Negative Ion PhotoelectronSpectroscopy239E. Some Thermochemical Uses of ElectronAffinities241F. Layout of Table 10: ExperimentalPhotoelectron Electron Affinities242III. Theoretical Determination of Electron Affinities 242A. Historical Background 2421. Theoretical Predictions of Atomic ElectronAffinities2422. Theoretical Predictions of MolecularElectron Affinities243B. Present Status of Theoretical Electron AffinityPredictions243C. Basis Sets and Theoretical Electron Affinities 244D. Density Functional Theory (DFT) andElectron Affinities245E. Layout of Tables 8 and 9: Theoretical DFTElectron Affinities247F. Details of Density Functional MethodsEmployed in Tables 8 and 9247IV. Discussion and Observations 248A. Statistical Analysis of DFT Results ThroughComparisons to Experiment and OtherTheoretical Methods248B. Theoretical EAs for Species with UnknownExperimental EAs251C. On the Applicability of DFT to Anions and theFuture of DFT EA Predictions251D. Specific Theoretical Successes 251E. Interesting Problems 2521. C

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Atomic and molecular electron affinities: photoelectron experiments and theoretical computations.

In this review we present the energies, configuration, and other properties of resonances (also called "compound states" and "temporary negative ions") in diatomic molecules. Much of the information is presented in the form of tables and energy level diagrams. Vibrational, rotational, and electronic excitation are discussed whenever these processes have given information on resonances; often these excitation processes proceed via resonances. The paper is divided according to molecular species (${\mathrm{H}}_{2}$, ${\mathrm{N}}_{2}$, CO, NO, ${\mathrm{O}}_{2}$), but the main conclusions are discussed by the nature of the processes involved.

Resonances in Electron Impact on Diatomic Molecules

There is a wide range of fundamental physical problems directly related to how pulsars function. Some of these are independent of the specific pulsar mechanism. Others relate directly to the physics of the pulsar and already shed some light on the properties of matter at high density (\ensuremath{\sim}${10}^{15}$ g/cc) and in strong magnetic fields (\ensuremath{\sim}${10}^{12}$ G). Pulsars are assumed to be rotating neutron stars surrounded by strong magnetic fields and energetic particles. It is somewhere within this "magnetosphere" that the pulsar action is expected to take place. Currently there has been considerable difficulty in formulating an entirely self-consistent theory of the magnetospheric behavior and there may be rapid revisions in the near future, which is all the more surprising since many of the issues involve "elementary" problems in electromagnetism. One interesting discovery is that charge-separated plasmas apparently can support stable static discontinuities.

Theory of pulsar magnetospheres

Atomic clocks have been instrumental in science and technology, leading to innovations such as global positioning, advanced communications, and tests of fundamental constant variation. Timekeeping precision at 1 part in 10 18 enables new timing applications in relativistic geodesy, enhanced Earth- and space-based navigation and telescopy, and new tests of physics beyond the standard model. Here, we describe the development and operation of two optical lattice clocks, both using spin-polarized, ultracold atomic ytterbium. A measurement comparing these systems demonstrates an unprecedented atomic clock instability of 1.6 × 10 –18 after only 7 hours of averaging.

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An atomic clock with $10^{-18}$ instability

A beam of ${\mathrm{O}}_{2}^{\ensuremath{-}}$ ions, extracted from a glow discharge in ${\mathrm{N}}_{2}$O, is crossed with the linearly polarized intracavity photon beam of an argon-ion laser (4880 \AA{}). Electrons photodetached at right angles to the crossed beams are energy filtered by a hemispherical analyzer. The electron energy spectra are characteristic of photodetachment from the ${v}^{\ensuremath{'}}=0$ state of ${\mathrm{O}}_{2}^{\ensuremath{-}}$ to the $X^{3}\ensuremath{\Sigma}_{g}^{\ensuremath{-}}$ and $a^{1}\ensuremath{\Delta}_{g}$ states of ${\mathrm{O}}_{2}$. Vibrational state analysis is facilitated by the use of isotopes. The electron affinity obtained is 0.440 \ifmmode\pm\else\textpm\fi{} 0.008 eV. Additionally, we have measured the relative transition probabilities as a function of final vibrational state and the angular distributions of the outgoing electrons. The relative intensities, corrected by the angular distributions, determine through Franck-Condon-factor analysis the internuclear distance for the negative ion. We find ${\mathcal{r}}_{e}^{\ensuremath{'}\ensuremath{'}}=1.341\ifmmode\pm\else\textpm\fi{}0.010$ \AA{} and therefore ${B}_{e}^{\ensuremath{'}\ensuremath{'}}=1.17\ifmmode\pm\else\textpm\fi{}0.02$ ${\mathrm{cm}}^{\ensuremath{-}1}$.

Molecular Photodetachment Spectrometry. II. The Electron Affinity of O2 and the Structure of O2

We apply laser photodetachment and photoelectron spectrometry for the first time to the study of molecular negative ions. We describe in detail the study of the nitric oxide in N${\mathrm{O}}^{\ensuremath{-}}$; a following paper reports results for ${\mathrm{O}}_{2}^{\ensuremath{-}}$. We use the N${\mathrm{O}}^{\ensuremath{-}}$ results to develop and illustrate in detail the principles and applications of the technique. A mass-selected N${\mathrm{O}}^{\ensuremath{-}}$ beam (680 eV) is crossed with a linearly polarized monochromatic (4880-\AA{}) argon-ion laser beam, and electrons photodetached into a $\frac{4\ensuremath{\pi}}{2000}$-sr solid angle perpendicular to the crossed beams are energy analyzed using a hemispherical electrostatic monochromator. The data yield a set of vertical detachment energies between vibrational states of N${\mathrm{O}}^{\ensuremath{-}}$ and NO, and relative intensities for these transitions. Angular distributions about the polarization direction are studied by rotating the laser polarization while maintaining the mutually perpendicular ion-beam-laser-beam-electron-collection geometry. For each transition we measure the anisotropy parameter $\ensuremath{\beta}$, corresponding to the form [$1+\ensuremath{\beta}{P}_{2}(cos\ensuremath{\theta})$] for the angular distribution. Several arguments, including data on N${\mathrm{O}}^{18\ensuremath{-}}$ photodetachment, are used to identify the initial and final vibrational states. Molecular rotational effects, and effects associated with the spin-orbit splitting of the final $\mathrm{NO}(X^{2}\ensuremath{\Pi})$ state are identified and included in the analysis. A Franck-Condon-factor analysis of the observed relative cross sections, parametrized by trial values of the N${\mathrm{O}}^{\ensuremath{-}}$ molecular constants, is used to determine that for N${\mathrm{O}}^{\ensuremath{-}}$ ${\ensuremath{\omega}}_{e}^{\ensuremath{'}\ensuremath{'}}=1470\ifmmode\pm\else\textpm\fi{}200$ ${\mathrm{cm}}^{\ensuremath{-}1}$, ${\mathcal{r}}_{e}^{\ensuremath{'}\ensuremath{'}}=1.258\ifmmode\pm\else\textpm\fi{}0.010$ \AA{}, and ${B}_{e}^{\ensuremath{'}\ensuremath{'}}=1.427\ifmmode\pm\else\textpm\fi{}0.02$ ${\mathrm{cm}}^{\ensuremath{-}1}$. Using these constants, the measured vertical detachment energy is reduced by rotational and spin-orbit effects to the electron affinity ${E}_{A}(\mathrm{NO})={24}_{\ensuremath{-}5}^{+10}$ meV.

Molecular Photodetachment Spectrometry. I. The Electron Affinity of Nitric Oxide and the Molecular Constants of NO

I will discuss the three general methods that are commonly used to transmit time and frequency information: one-way methods, which measure or model the path delay using ancillary data, two-way methods, which depend on the symmetry of the delays in opposite directions along the same path, and common view, in which several stations receive data from a common source over paths whose delays are approximately equal. I will describe the advantages and limitations of the different methods including uncertainty estimates for systems that are based on them.

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A review of time and frequency transfer methods

In this article, I will review the definition of time and time interval, and I will describe some of the devices that are used to realize these definitions. I will then introduce the principles of time and frequency metrology, including a discussion of some of the types of measurement hardware in common use and the statistical machinery that is used to analyze these data. I will also introduce various techniques of distributing time and frequency information, with special emphasis on the global positioning system satellites. I will then discuss the advantages of clock ensembles and a prototype time-scale algorithm. I will conclude with a discussion of how clocks are synchronized to remote servers using noisy and poorly characterized transmission channels.

Introduction to time and frequency metrology

We have conducted several time-transfer experiments using the phase of the GPS carrier rather than the code, as is done in current GPS-based time-transfer systems. Atomic clocks were connected to geodetic GPS receivers; we then used the GPS carrier-phase observations to estimate relative clock behavior at 6-minute intervals. GPS carrier-phase time transfer is more than an order of magnitude more precise than GPS common view time transfer and agrees, within the experimental uncertainty, with two-way satellite time-transfer measurements for a 2400 km baseline. GPS carrier-phase time transfer has a stability of 100 ps, which translates into a frequency uncertainty of about two parts in 10/sup -15/ for an average time of 1 day.

Judah Levine

Papers

Molecular Photodetachment Spectrometry. II. The Electron Affinity of O2 and the Structure of O2

Molecular Photodetachment Spectrometry. I. The Electron Affinity of Nitric Oxide and the Molecular Constants of NO

A review of time and frequency transfer methods

Introduction to time and frequency metrology

Carrier-phase time transfer