Annotated References: [1] Bruce Schneier, Applied Cryptography, 2e, John Wiley & Sons, 1996. The best one volume, publicly available, non-mathematical, approachable by us ordinary folk, survey of the current state of cryptography. Very good coverage and excellent evaluation of the field, but not much history, and so it is, unbelievably, incomplete. On the other hand it's still a single volume, though only just; anything more might have been beyond the bookbinder's art, particularly in the paperback edition. The bibliography is a superb entry into the public literature, so those who wish to cover the field to completion (likely possible only for those with copious free time!) have a very significant assist. See also his article 'Why Cryptography is Hard' at http://www.counterpane.com which is excellent. [7] is comparable in many ways. [2] Donald Knuth, The Art of Computer Programming, vol 2: Semi-Numerical Algorithms, 2e, Addison Wesley, The third edition is due before the end of the century. Knuth is an incredible man; one of the intellectual giants of the computer field. As complete coverage as exists in one volume of randomness and tests for it. Anything more complete or current will be full blown specialist material. It's not clear there is any single more complete reference. It may be of some interest that Knuth's first publication was in MAD Magazine. He was, if I recall correctly, 10. [3] W H Press, S A Teukolsky, W T Vetterling & B P Flannery, Numerical Recipes in C, 2e, 1992, Camb Univ Press. Almost comprehensive coverage of numerical computing in a single, thick, volume! There are versions in Pascal, FORTRAN, and BASIC, though only the FORTRAN and C editions have been taken into a second edition. More astonishing, it is actually readable, at least a little, and the authors don't adopt the stuffy academic soporific style so common in such books. It's entertaining every so often, and may even evoke a smile or two, almost uniquely in your author's experience with such references (another is the Art of Electronics by Horowitz and Hill which has frequent 'dim bulb idea' sections containing tempting, but crackpot, implementations of the material just covered in the preceding chapter). Also Camb Univ Press -- do we detect the existence of a reader-friendly technical editor in this, or are two superb and well written, even humorous, technical books from the same publisher mere coincidence? Readers who are not mathematical may find most of Recipes more than a little much. But the coverage of random numbers (in chapter 7) is much shorter and more direct than [2], covers material about generator algorithms in software that [1] does not (including portability of source code across machine architectures), and includes some perspective on actual real world implementations of random number generators supplied with languages or found in support libraries. Compilers and CPU architectures often have effects on the behavior of programs which are not obvious from the ostensible program source code itself -- a considerable degree of low cunning and curmudgeonly suspicion is well-warranted for numerical, as for all other, programmering. Users (including would-be cryptographic programmers and system designers) should find the authors' observations extremely interesting, and equally depressing. Their comments about bugs found in commercial compilers whilst attempting to test their routines (in the Preface to the 2nd ed) are very relevant to anyone contemplating any numeric programming; note that cryptographic code is a specialized subset of numeric programming generally. It's not a pretty picture. A more attractive picture is their enjoyment, and recommendation, of the software they used to write the book (also in the Preface to the 2nd ed: note that much of that software is available without charge, in source code, via the Internet and elsewhere; contact the Free Software Foundation in Boston, Massachusetts, for much of it). [4] S K Park & K W Miller, Random Number Generators: Good Ones are Hard to Find, Comm. of the ACM, vol 31, p 1192f, 1988. An historical review of some of the blunders in the random number generation field, and a theoretical overview of the problem. Not only is the arena of random number generators (commercial, non- commercial, or whatever) not a pretty picture, it's positively ghastly. Great intestinal fortitude is required. Caveat random number generators! [5] P Beckmann, The Story of Pi, 3e, 1974, multiple editions. The incredible folly of those who are ignorant of technical issues and without intellectual humility, or alternatively, are blandly certain of themselves and their beliefs, and who proceed regardless. Each edition includes typo corrections and additional material on using computers in calculating the value of pi, but they're otherwise equivalent. The book concentrates on a tiny corner of mathematical history and contains the story of the American State Legislature which came within a gnat's eyebrow (two committees of and the lower house, and one committee in the upper) of enacting a law making the ratio of the circumference of a circle to its diameter equal to exactly four within the boundaries of that state (within the lives of many people still living today -- in 1897!!). All who remain ignorant of technical matters, yet who enact laws or regulations about them, risk the 'eternal horselaugh'; that legislature will never escape well-deserved derision. This is immortality of a sort those folks surely didn't want. The text of the bill, and much additional source material from the history of pi, is in L Berggren and J & P Borwein, PI, A source book, Springer Verlag, 1997. There is a more recent book about the history of pi (The Joy of Pi by Blattner), but its typographic design is so bizarre that it is effectively unreadable. Were it readable, it would be a quite reasonable addition / alternative to Beckmann. There is also an excellent recent book on the number 'e' (E Maor, e: the story of a number, Princeton Univ Press, 1994), and a Dover book on the golden section number, phi. Neither has anything obvious to do with cryptography, but if you like Beckmann's subject, you'll enjoy the others. [6] D Kahn, The Codebreakers, Macmillan, 1967, (revised and updated edition, 1996, Scribners). A little out of date because it was published before asymmetric key cryptography was publicly announced in the 70's, and before much was known about Bletchley Park or Colossus or the Army / FBI / NSA cryptographic efforts against Russian spies in the late '40s and early '50s, and before DES, and before Clipper and Capstone. The reporting is supposed to have been finished by about '63 or '64. But withal, it's still the most readable, reliable, and entertaining reference to the history of, and to the more or less easily approachable theory of, cryptography. Not technical, but not gee whiz! simplistic either. The '96 edition has a too brief additional chapter on events actually happening, or disclosd through declassification, since the original publication. There have been several important disclosures of important WWII era cryptographic events, and several important cryptographic developments. More complete coverage of them by Kahn would be most welcome. Very very highly recommended, as are Kahn's other books, eg Kahn on Codes, Macmillan, 1993, and Seizing the Enigma, Houghton Mifflin, 1991. The Enigma book was the best readily available account of the long struggle over German Naval Enigma when it was published. There are now several other quality accounts as well. Another book on the Enigma episode is The Hut Six Story: Breaking the Enigma Codes, G Welchman, McGraw- Hill, 1982; Welchman worked with Turing on Naval Enigma. Some of the views of participants at Bletchley Park are in F H Hinsley & A Stripp, Code Breakers. The overall official view is British Intelligence in the Second World War, 4 vols, edited by H Hinsley. Hodges biography of Turing, The Enigma, is superb, but is so concentrated on Turing that it can give an unbalanced impression. Certainly Turing built on the work of others in his cryptographic work at Bletchley Park; his colleagues working on Naval Enigma were hardly negligible. But in a wider sense, Hodges is correct that Turing was one of those very unusual minds who appear now and then; many of his contributions in other areas were also spectacularly unanticipated. Much like Kurt Godel, or Claude Shannon in many ways. [7] A Menezes, P C van Oorschot & S Vanstone, Handbook of Applied Cryptography, CRC Press, 1997. Less anecdotal and more heavily technical and mathematical than [1]. Worth looking at if you are comfortable with the mathematical level. Among other things, it covers such technical detail as that concealed within the phrase, "...and then have PGP generate a pair of RSA keys for you". If you aren't interested in the technical side, or haven't the maths background to follow it, then [1] is a better choice, though in making a reporting of much of the literature intelligible to the less than mathematically accomplished, [1] is necessarily brief on any particular topic. For the original technical material see the excellent bibliographies in [1] or here. If you care most about the plain technical side and less about the history and literature of it all, dive straightaway into the HoAC. [8] NSA, The Venona Project. See http://www.nsa.gov/docs/venona/venona.html. This site has the publicly released account of how the FBI and the proto-NSA managed to break some of the one-time pad traffic between Soviet spies in the US and Moscow. Some of the traffic was related to the atom bomb spy ring the Soviets ran during WWII. The Soviets are publicly known to have used (somewhat sloppily on occasion) one-time pads at least as early as the 1930's and at least as late as Colonel Abel's arrest in '57 and the Kroger's UK arrest in the early '60s. See Bombshell by Albright and Kunstel for additional information on several aspects of the Venona Project decryptions. [9] B Schneier, et al, The Electronic Privacy Papers, J Wiley and Son, 1997. A collection of documents relating to cryptography and privacy. Many were made available to the public as the result of a Freedom of Information Act lawsuit by the Electronic Privacy Information Center. Taken together, they provide very good reason to believe that NSA, and the US government generally, are -- and have long been -- seriously committed to an attempt to control all cryptography, including shaping the adoption of standards and policies here and abroad by both public argument or private pressure. The underlying assumption seems to be that if enough people can be cowed or compelled into abandoning, or never adopting, adequate cryptography then NSA can continue a decades long policy of wholesale eavesdropping. This collection makes chilling reading for computer folk committed to open computing (eg, the Free Software Foundation, the League for Programming Freedom or any of their supporters) and to all those for whom the US Federal Constitution and its Amendments (including the 'Bill of Rights') are important (ie, those who believe that limited government is most compatible with citizen liberty). In this connection, it is probably useful, for those who are inclined to take the seemingly expedient route, to remember that the Constitution, including all those pesky Amendments, is the supreme law of the land in the US. See also [13 & 18] and appendices b & c. [10] R J Anderson, "Why Crypto-systems Fail", Comm of the ACM v37, n11, 11.94, p32ff. He also has an article of the same title in 1st ACM Conf on Computer and Comm Security, ACM Press, 1993, p215ff. (See also the Schneier article referenced in [1]). His home page is www.cl.cam.ac.uk/users/rja14/. [11] Full Lotus is in British Columbia. Look 'em up! [12] J Nechvatal, Public-key Cryptography, 12/90. Nechvatal is from the National Computer Systems Laboratory, National Institute of Standards and Technology (formerly NBS) in Gaithersburg, MD. This is a brief paper surveying a part of modern cryptography from a mathematical viewpoint. If you'd like a sense of the underlying math, and can cope with the formality and abstraction, this paper will be interesting. It includes a reasonable, though brief, discussion of asymmetric algorithm cryptanalysis as a bonus. It's been widely available on the Internet. It has very extensive references. A book with some communications theory (Nechvatal assumes the reader is basically familiar with it) and wider coverage of cryptography than Nechvatal, but with less complete mathematics, is D Welsh, Codes and Cryptography, Oxford Univ Press, 1988. As mathematical material goes, it's well written. It's oriented toward those with some mathematical maturity, but is a course text and so leaves much to exercises and student enterprise. It's brief, which is good for those not aspiring to careers in mathematical cryptography, but covers communication theory, and Shannon's multiple contributions to it and to cryptography, well. Shannon and Weaver, The Mathematical Theory of Communication, Univ of Illinois Press, does not cover as much as Welch (and, having been written in the late '40s, is far less complete regarding recent cryptography), but is an excellent introduction to information theory, which underlies much of cryptographic security theory. The presentation is accessible to the non-mathematician, but does require some thought. Shannon was extraordinarily subtle. Shannon's articles in the Bell System Technical Journal (1949), including Communication Theory of Secrecy Systems, are also well worth reading for those interested in the origins of the modern cryptographic public literature. [13] W Diffie & S Landau, Privacy on the Line: the politics of wiretapping and encryption, MIT Press 1998. Diffie is one of the public inventors of asymmetric key encryption and Landau is a Professor of Computer Science. Like [9 & 14], this is a disturbing book for civil rights advocates. [14] P R Zimmerman, The Official PGP User's Guide, MIT Press 1995. A brief and readable account of the design and operations of a modern high quality crypto system. Of particular interest to readers of this summary are the Foreword (by J P Barlow), Chap 7 Snake Oil, Chap 10 A Peek Under the Hood, and Chap 11 Vulnerabilities. Zimmerman writes clearly, and briefly, on real issues in real crypto systems. He also provides a view of the political and pressure issues which arose in making very good cryptography available to almost everyone. Specifically, he was for a very long time the target of a criminal investigation by the US Federal Government by reason of his design of the PGP crypto system. Such facts will likely be disturbing to anyone concerned about government power intruding into citizens' private lives. Note that the book describes the 2.6.2 version of PGP; there is a more recent edition covering later versions. The PGP crypto system has been acquired by a commercial company, Network Associates Inc, since that version. NAI have produced several new versions of PGP; some of which continue to be available in source code (at least through v 6.5.8 according to Zimmerman, in his announcement that he was leaving NAI). At this writing, none has been available long enough to have had the intense volunteer scrutiny for errors and omissions that the freeware releases had. They may each be perfectly acceptable and as good as PGP ever was, but without public review (and enough time to do it) ... It is to be hoped that each of these newer versions are as crypto competent as the version described here and as well supported by good documentation. Note also that the Free Software Foundation has produced a GPL'd implementation of PGP under the name GPG (it's supported – financially -- by the German Government!). GPG does not have so complex a history as PGP and so provides a way to evade at least some of that confusion. See [19] for more. [15] M Blaze, W Diffie, R Rivest, B Schneier, T Shimomura, E Thompson, M Wiener, "Minimal Key Lengths for Symmetric Cyphers to Provide Adequate Commercial Security", 1996. See http://theory.lcs.mit.edu/~rivest/bsa- final-report.ascii. [16] J A Reeds & P J Weinberger, File Security and the Unix System 'crypt' command, AT&T Bell Labs Technical Journal, vol 63, nr 8, Oct 1984. This paper is an analysis of the cryptographic security of an encryption algorithm designed at Bell Labs. The algorithm is insecure and should NEVER be used for any serious purpose, but the paper is a short, and more or less approachable, example of the kind of work involved in modern cryptographic analysis. The Dancing Men (by A C Doyle) and The Gold Bug (by E A Poe) both include simple cryptanalysis of single alphabet substitution cyphers, if you'd like to see how things were done in older times. Substitution cyphers of this sort were the state-of-the-cryptographic-art in ancient Greece and Rome, but have been pretty much obsolete since about the end of the 1st millennium, though perhaps usable here and there when the opposition can be known to be particularly simple-minded. [17] J Bamford and W Madsen, The Puzzle Palace, 2e, Penguin Books, 1995. Not much is in print about NSA, the US Government crypto and signals intelligence (ie, eavesdropping) agency. This is the best of a small lot. Bamford has written a new book on NSA -- Body of Secrets: Anatomy of the NSA. It is also very interesting. [18] K Dam & H Lin, eds, Cryptography's Role in Securing the Information Society, National Academy Press, 1996. This is the report Congress asked the National Research Council to produce in 1993. It is available through www.nap.edu/readingroom/books/crisis. On the whole, it does not support the NSA / FBI / International Association of Chiefs of Police position on control of cryptography. One may expect that NSA et al were not pleased. [19] Web resources. These following sites are an extremely small sampling of Web crypto pages; it's possible to spend eternities chasing crypto links around the world. However, note that information on the Internet, including the Web, has to be very carefully handled. For instance, have you heard that spending too much time on the Web causes feeblemindedness? How much is 'too much' varies with the individual, of course. There is much misinformation, plausible and implausible, on the 'Net. Use great care before relying on anything found there. The first three references are especially concerned with Philip Zimmerman's PGP, the freeware and commercially available crypto system. www.pgpi.org, www.pgpinternational.com, www.pgp.com/phil, http://csrc.nist.gov/encryption/, www.epic.org, www.eff.org, and www.cdt.org. The following site contains an extensive history, with many elaborate diagrams, of important historical ciphers and machines: www.home.ecn.ab.ca/~jsavard/crypto. [20] R L Benson & M Warner, eds., Venona: Soviet Espionage and the American Response, 1939-1957, NSA & CIA, 1996. [21] R L Benson, Introductory History of Venone and Guide to the Translations, Venona Historical Monograph nr 1, NSA, Fort Meade, Maryland, 1995. [22] R L Benson, The 1942-43 New York-Moscow KGB Messages, Venona Historical Monograph nr 2, NSA, Fort Meade, Maryland, 1995. [23] F L Bauer, Decrypted Secrets: Methods and Maxims of Cryptology, Springer Verlag, 1997. Both technical information on cryptographic subjects and stories and anecdotes. David Kahn thought it was the best book on cryptography he'd read, according to a review. However, the book was originally written in German and its origins shine through the translation. The presentation of the technical material, and even of some the historical material, suffers somewhat as a result. There are even some considerable oddities as, for instance, the account of the reason that newly elected President Edgar Hoover's new Secretary of State (ie, Stimson) gave for shutting down Yardley's cryptographic operation. Nonetheless, this an excellent book and worth reading; it is neither a popular account (as is [24]) nor a technical treatise on cryptography (as is Welch's book (see [12]), or [16]) and therefore misses both audiences to some extent. [24] S Singh, The Code Book, Doubleday, 1999. Like [6], an anecdotal survey of cryptographic history, but much less comprehensive and more anecdotal. Includes the era since [6] was completed -- asymmetric algorithms, inexpensive computers, ... Singh chooses specific events in crypto history on which to base his account. Well written by a science writer with a technical background. The level of technical detail is uneven partly as a result of Singh's choice to concentrate on particular events as a narrative structure, the language is eccentric in places, (eg, 'scramblers' is used to mean Enigma style rotors, and 'mangler function' is used for what is elsewhere called 'substitution boxes' in DES), and the language is British, which sounds unusual to American ears. But none of this much affects the basic account. Good on personalities in the incidents covered (eg, the invention of asymmetric key cryptography, of the 'RSA' algorithm, and of Diffie-Hellman key exchange, at GCHQ well before their public disclosure by Diffie & Hellman / Merkle and Rivest / Shamir / Adelman). (NSA has also made a public claim of knowing about 'two key' encryption (ie, Diffie-Hellman, more or less) around 1966; no further information is available in support of this claim). Singh discusses Babbage's non-publicly disclosed general break of polyalphabetic ciphers (in the Vigniere variation). [25] J C Masterman, The Double-Cross System, Yale Univ Press, New Haven, 1972, a 1945 account of the extraordinary success of British Intelligence in turning German agents during the War. Well written by one of the chief participants in the 'XX Committee' responsible. Originally an internal government memorandum and probably incomplete as a result of British security restrictions applicable when written as well as when published. [26] R F Newcomb, Abandon Ship!, a 1958 account of the USS Indianapolis disaster, recently revised and to be published in a new edition in early 2001 by HarperCollins. The new edition will include formerly classified information about the cryptanalytic reasons Captain McVay was lied to by the Navy about known enemy hazards to his ship before the last leg of its last voyage. And about the multiple additional screw-ups (some cryptographic) which allowed about 300 men to die when the ship went down, or for about 600 of them to die (mostly of shark attacks) in the four unnecessary days they were in the water before those who remained were accidentally found and recovered. [27] Steven Levy, Crypto, Viking, 2001. A popular account of US cryptographic policy from about 1970 to 2000, with some crypto and crypto history thrown in. Coverage of this has long been needed since that policy has long been fundamentally incoherent technically, and remains opaque (even in its current ('relaxed', but only your lawyer can tell) version. It's told primarily from the perspective of the public inventors of asymmetric key algorithms, especially Whitfield Diffie, an extremely colorful character. Levy is a technology editor at Newsweek and the author of Hackers, among many others. [287] Martin Gardner, Codes, Cyphers and Secret Writing, Dover, 1972. A well-written elementary account of simple cyphers and secret writing. Suitable for a younger audience. His bibliography has pointers to not only books in this class, but also to some more advanced treatments. It is interesting to compare his evaluation of Fletcher Pratt's book with Kahn's in [6]. [29] JE Haynes & H Klehr, Venona: Decoding Soviet Espionage in America, Yale Univ Press, 1999. Written by two historians who have traveled to Russia and examined some of the archives (eg, of the Communist Party USA) now (or formerly) open to research. The book is actually less about cryptanalysis than it is about the personnel and activities of Soviet spies in the US, especially after the Soviet espionage effort seriously expanded in the late '30s. It does give a clear picture of what eventually came to be called the Venona project, and some detail on the way the KGB / GRU managed to blot their copy book in providing break opportunities into their one-time pad system. [30] G Moody, Rebel Code, 2001. A journalist's account of one side of the open source software movement. The emphasis is on Linux (Linus Torvalds) and the Free Software Foundation (Richard Stallman). the executive summary: cryptography © W Wilgus, 2000; all rights reserved. Reproduction prohibited. 1