Advances in computer system security

878 zyx zyxw zyxw zy zyxwvutsrqponmlk zyxwvutsr zyxwvutsrq zyxwvutsrqp zyxwvut zyxwvutsrqpo PROCEEDINGS OF THE IEEE, VOL. 70, NO. 8, AUGUST 1982 Book Reviews l%e following reviews were sekted from rhose recently published in IEEE TRANSACTIONS and Gro~qlSocie~y Magazim and Novsk t t n 7hcy me reprinted here to make them ecmmietuly avoiloblc IO lhc many readers who othenvk mighl not have ma& occm 10 them. Eeeh review isfoUowd by an idmrjfiaaion of its origiml source. various ‘Ihory. Nadhear System TBe VdtcnJwciaea Approtcb-Wilson J. Rugh (Baltimore: Johns Hopkins University Press, 1981, 325 pp.). Reviewed by John L. Wyatt,Jr., Deprtmmt of Eleciriozl Engtneeriag and Computer Science, M ~ c h u a e t t sIW’tute of Technobg? Gzmbridge, MA 02139. zyxwvut This is, to the best of my knowledge, the f h t and only Engtirh language text on the Volterra series in relation to modern state-varisbfe methods in system dynamics. Following is a brief summary and explanation of the contents. Chapter 1, “Input/Output repraentations in time domain” introduces the basic “degree-n homogeneous system” y(f)=l-...j-h.(u -OD only steers the reader to related papers but also explains what is in than and how each fits into the subject Any study of the literature should begin here. I believe there is only one remotely comparable work published in English: Schetzen’s recent work. m e Voltam and Wknw Thsriesof Nonlinccp Systems [ 1 1. Schetzm’s book contains much more material than Rugh’s on the Wiener series and the stochastic case in general but suffers from the complete omigion of state-space ideas Therefore, Schetzen may appeal to workers in communicatiom, and Rugh should be the better reference for control researchers A readily a d b l e account ofSchetzen’s approach appean in [2],and areview of his book recently appeared in ciracitsQ n d Systems Magazine [ 3 1. ~,..., un)u(f-or)... REFERENCES [ 1 1 M. Schetzen. The V d t e m and Wiener Theodu of Nonlinear S p J o h n Wfley: New YorL, 1980. [ 2 ] M. Schetr.cn, Wonlinearsystem modelling baaed on the W iener t h t o r y , ” k . IEEE,voL 69. pp. 1557-1572, DGC 1981. [ 31 R.J.P. de Figueiredo. “Review of Thc Voltem and Wiener ?%e& of Nonifncm Syrtcms,“ IEEE CYrcujta and S y m s Magazine, v d 3, pp. 26-27, Sept. 1981. tmu Reprinted from IEEE Circuits and System M m e . vot 4, no. 2, pp. 24-25, June 1982. -OD series is an extension of the Taylor series to functicn spaces. The burden of notation, a reat problem in this subject, is eased by the author’s decision to consider only h@e-input/singleoutput systems throughout Chapter 11, “Input/Output representations in the transform domain” introduces Laplace Transform-like techniques for the study of Volterra systems The transform representation of the degree-n homogeneous system in (1) is a function of n complex variables. Chapter IDis entitled “Obtaining inputloutput representations from differential-equation descriptions” Chapter IV, “Realization theory” deals with the inverse of the problem s t u d i e d m Chapter III. Chapter V, “Response characteristics of stationary systems”shows how to calculate the harmonics and subharmonics generated when the sum of several sinusoids is fed through a degreen homogeneous system. This is a topic of practical importance in analyzing the effect of slight nonlinearities in audio systems The author introduces random inputs and explains the calculation of crowcorrelationsandcros-spectral densities This leads to the famous Wiener series, in which the central idea is to find a sequence of polynomial Volterra systems with outputs which are orthogonal when white noise inputs are applied. “Discrete-Time systems” chapter VI, provides the reader with a chance to consolidate his knowledge by transferring the entire previous development to the analytically (but not always notationally) simpler discretetime case. An interesting theme running through this section is the relation between degree-n homogeneous systems and multidimew sional linear systems, for example digital image filters Chapter VII, “Identification,” addresses the problem of inffmingthe kernels (the function h,, in (1) is a kernel) for a polynomial system, using first sinusoidal and then white noise inputs The author makes it clear that much remains to be done inthis area This is a calculation-oriented or “how to” book, suitable as a text for asecond-year graduate course or seminar on nonlinear systems A number of problems is included at the end of each chapter. Rugh is clearly awareof the deeper mathematical issues involved and has chosen not to emphasize them. This will be an advantage for those whose goal is to use Volterra sriw as a practical calculating or modeling too, but others with an interest in the fundamental mathematics of systems theory may be disappointed in the casual treatment given to certain topics,especially convergence.Even this latter group, however. win find the book indispensable as an introduction to the subject and its literature. The style is breezy, charming, unpretentious. Rugh’sway of giving references is adelight and greatly enhances the book’s v h e . Each chapter ends with a section called “Remarks and references,” which not A collection of 28 reprints dealing with computer security, of which the fonowing are the most interesting, “F’rivacy and Authentication: An Introduction to Cryptography,” W. Diffie and M. E. Hellman, Proc IEEE, 1979;“Data Encryption Standard,” FIPS PUB 46, National Bureau of Standards 1977;“Structured Design of Substitutiodmnutation Encryption Networks,” J. Kam and G. Davida, IEEE TRANSACTIONS ON COMPUTERS, 1979; “An OverviewofPublicKey Cryptography,” M. E. Hellman, IEEE Communimtions Society Magazine, 1978; “Protocols for Public Key Cryptosystemq” R. C. Merkle, Proceedings, 1980 Symposium on Security and Privacy; “Security of Computer Communications,” D. K. Branstad, IEEE Communications Society Magazine, 1978; “Using Encryption for Authentication in aLargeNetwork of Computers,” R. M. Needham and M. D. Schroeder, Communications of the ACM, 1978. The frnal section of the book reprints the Federal Government’s Privacy Act of 1974 and the Federal Computer Crime Bill S. 240. Most of the articles in this collection are reprinted from conference proceedings, qecially the AFIPS conference, and this bias is reflected in their contents, which emphasizes discussionrather than mathematics Three of the articles are reprinted from the November 1978 special issue of the IEEE Communications Society Magazine;none from IEEE TRANSACTIONS ON INFORMATION THEORY. Any anthology is necessarily a personal selection; still, if the reviewer were to make a collection of the best recent papers in computer security and cryptography, it would look nothing like this one.Where are L Adleman, R. Morris, M. 0. Rabin, J. Reeds, R. Rivest, A. Shamir? Reprintedfrom IEEE TmnaWionr on Information Theory, v d IT-28, no. 3, p. 557, May 1982. Protocob and Techniques f a Data C o m m d c a o i t u Networks-Franklin F. Kuo, Ed. (Englewood Cliff& NJ: Prenticcdall, 1981, xi+468 pp.). Reviewed by Michael Kap&n, INRS-Telecommunications, Montreal, Que, Canada Contents. 1) Packet Communication Technology (Vincent E. Cero; 2) Transport Protocols for Computer Networks (Carl A. Sunshine); 3) Terminal, File Transfer, ind Remote Job Protocols for Heterogeneo w Computer Networks (John D. Day); 4) Routing and Flow Control