Tag Archives: history of cryptography

List of Old NSA Training Videos

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/09/list-of-old-nsa-training-videos.html

The NSA’s “National Cryptographic School Television Catalogue” from 1991 lists about 600 COMSEC and SIGINT training videos.

There are a bunch explaining the operations of various cryptographic equipment, and a few code words I have never heard of before.

On the Voynich Manuscript

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/08/on-the-voynich-manuscript.html

Really interesting article on the ancient-manuscript scholars who are applying their techniques to the Voynich Manuscript.

No one has been able to understand the writing yet, but there are some new understandings:

Davis presented her findings at the medieval-studies conference and published them in 2020 in the journal Manuscript Studies. She had hardly solved the Voynich, but she’d opened it to new kinds of investigation. If five scribes had come together to write it, the manuscript was probably the work of a community, rather than of a single deranged mind or con artist. Why the community used its own language, or code, remains a mystery. Whether it was a cloister of alchemists, or mad monks, or a group like the medieval Béguines—a secluded order of Christian women—required more study. But the marks of frequent use signaled that the manuscript served some routine, perhaps daily function.

Davis’s work brought like-minded scholars out of hiding. In just the past few years, a Yale linguist named Claire Bowern had begun performing sophisticated analyses of the text, building on the efforts of earlier scholars and on methods Bowern had used with undocumented Indigenous languages in Australia. At the University of Malta, computer scientists were figuring out how to analyze the Voynich with tools for natural-language processing. Researchers found that the manuscript’s roughly 38,000 words—and 9,000-word vocabulary—had many of the statistical hallmarks of actual language. The Voynich’s most common word, whatever it meant, appeared roughly twice as often as the second-most-common word and three times as often as the third-commonest, and so on—a touchstone of natural language known as Zipf’s law. The mix of word lengths and the ratio of unique words to total words were similarly language-like. Certain words, moreover, seemed to follow one another in predictable order, a possible sign of grammar.

Finally, each of the text’s sections—as defined by the drawings of plants, stars, bathing women, and so on—had different sets of overrepresented words, just as one would expect in a real book whose chapters focused on different subjects.

Spelling was the chief aberration. The Voynich alphabet—if that’s what it was—appeared to have a conventional 20-odd letters. But compared with known languages, too many of those letters repeated in the same order, both within words and across neighboring words, like a children’s rhyme. In some places, the spellings of adjacent words so converged that a single word repeated two or three times in a row. A rough English equivalent might be something akin to “She sells sea shells by the sea shore.” Another possibility, Bowern told me, was something like pig Latin, or the Yiddishism—known as “shm-reduplication”—that begets phrases such as fancy shmancy and rules shmules.

Whale Song Code

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/04/whale-song-code.html

During the Cold War, the US Navy tried to make a secret code out of whale song.

The basic plan was to develop coded messages from recordings of whales, dolphins, sea lions, and seals. The submarine would broadcast the noises and a computer—the Combo Signal Recognizer (CSR)—would detect the specific patterns and decode them on the other end. In theory, this idea was relatively simple. As work progressed, the Navy found a number of complicated problems to overcome, the bulk of which centered on the authenticity of the code itself.

The message structure couldn’t just substitute the moaning of a whale or a crying seal for As and Bs or even whole words. In addition, the sounds Navy technicians recorded between 1959 and 1965 all had natural background noise. With the technology available, it would have been hard to scrub that out. Repeated blasts of the same sounds with identical extra noise would stand out to even untrained sonar operators.

In the end, it didn’t work.

Declassified NSA Newsletters

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2024/04/declassified-nsa-newsletters.html

Through a 2010 FOIA request (yes, it took that long), we have copies of the NSA’s KRYPTOS Society Newsletter, “Tales of the Krypt,” from 1994 to 2003.

There are many interesting things in the 800 pages of newsletter. There are many redactions. And a 1994 review of Applied Cryptography by redacted:

Applied Cryptography, for those who don’t read the internet news, is a book written by Bruce Schneier last year. According to the jacket, Schneier is a data security expert with a master’s degree in computer science. According to his followers, he is a hero who has finally brought together the loose threads of cryptography for the general public to understand. Schneier has gathered academic research, internet gossip, and everything he could find on cryptography into one 600-page jumble.

The book is destined for commercial success because it is the only volume in which everything linked to cryptography is mentioned. It has sections on such-diverse topics as number theory, zero knowledge proofs, complexity, protocols, DES, patent law, and the Computer Professionals for Social Responsibility. Cryptography is a hot topic just now, and Schneier stands alone in having written a book on it which can be browsed: it is not too dry.

Schneier gives prominence to applications with large sections.on protocols and source code. Code is given for IDEA, FEAL, triple-DES, and other algorithms. At first glance, the book has the look of an encyclopedia of cryptography. Unlike an encyclopedia, however, it can’t be trusted for accuracy.

Playing loose with the facts is a serious problem with Schneier. For example in discussing a small-exponent attack on RSA, he says “an attack by Michael Wiener will recover e when e is up to one quarter the size of n.” Actually, Wiener’s attack recovers the secret exponent d when e has less than one quarter as many bits as n, which is a quite different statement. Or: “The quadratic sieve is the fastest known algorithm for factoring numbers less than 150 digits…. The number field sieve is the fastest known factoring algorithm, although the quadratric sieve is still faster for smaller numbers (the break even point is between 110 and 135 digits).” Throughout the book, Schneier leaves the impression of sloppiness, of a quick and dirty exposition. The reader is subjected to the grunge of equations, only to be confused or misled. The large number of errors compounds the problem. A recent version of the errata (Schneier publishes updates on the internet) is fifteen pages and growing, including errors in diagrams, errors in the code, and errors in the bibliography.

Many readers won’t notice that the details are askew. The importance of the book is that it is the first stab at.putting the whole subject in one spot. Schneier aimed to provide a “comprehensive reference work for modern cryptography.” Comprehensive it is. A trusted reference it is not.

Ouch. But I will not argue that some of my math was sloppy, especially in the first edition (with the blue cover, not the red cover).

A few other highlights:

  • 1995 Kryptos Kristmas Kwiz, pages 299–306
  • 1996 Kryptos Kristmas Kwiz, pages 414–420
  • 1998 Kryptos Kristmas Kwiz, pages 659–665
  • 1999 Kryptos Kristmas Kwiz, pages 734–738
  • Dundee Society Introductory Placement Test (from questions posed by Lambros Callimahos in his famous class), pages 771–773
  • R. Dale Shipp’s Principles of Cryptanalytic Diagnosis, pages 776–779
  • Obit of Jacqueline Jenkins-Nye (Bill Nye the Science Guy’s mother), pages 755–756
  • A praise of Pi, pages 694–696
  • A rant about Acronyms, pages 614–615
  • A speech on women in cryptology, pages 593–599

Mary Queen of Scots Letters Decrypted

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/02/mary-queen-of-scots-letters-decrypted.html

This is a neat piece of historical research.

The team of computer scientist George Lasry, pianist Norbert Biermann and astrophysicist Satoshi Tomokiyo—all keen cryptographers—initially thought the batch of encoded documents related to Italy, because that was how they were filed at the Bibliothèque Nationale de France.

However, they quickly realised the letters were in French. Many verb and adjectival forms being feminine, regular mention of captivity, and recurring names—such as Walsingham—all put them on the trail of Mary. Sir Francis Walsingham was Queen Elizabeth’s spymaster.

The code was a simple replacement system in which symbols stand either for letters, or for common words and names. But it would still have taken centuries to crunch all the possibilities, so the team used an algorithm that homed in on likely solutions.

Academic paper.

EDITED TO ADD (2/13): More news.

Charles V of Spain Secret Code Cracked

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/11/charles-v-of-spain-secret-code-cracked.html

Diplomatic code cracked after 500 years:

In painstaking work backed by computers, Pierrot found “distinct families” of about 120 symbols used by Charles V. “Whole words are encrypted with a single symbol” and the emperor replaced vowels coming after consonants with marks, she said, an inspiration probably coming from Arabic.

In another obstacle, he used meaningless symbols to mislead any adversary trying to decipher the message.

The breakthrough came in June when Pierrot managed to make out a phrase in the letter, and the team then cracked the code with the help of Camille Desenclos, a historian. “It was painstaking and long work but there was really a breakthrough that happened in one day, where all of a sudden we had the right hypothesis,” she said.

Gus Simmons’s Memoir

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/03/gus-simmonss-memoir.html

Gus Simmons is an early pioneer in cryptography and computer security. I know him best for his work on authentication and covert channels, specifically as related to nuclear treaty verification. His work is cited extensively in Applied Cryptography.

He has written a memoir of growing up dirt-poor in 1930s rural West Virginia. I’m in the middle of reading it, and it’s fascinating.

More blog posts.

More Military Cryptanalytics, Part III

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/08/more-military-cryptanalytics-part-iii.html

Late last year, the NSA declassified and released a redacted version of Lambros D. Callimahos’s Military Cryptanalytics, Part III. We just got most of the index. It’s hard to believe that there are any real secrets left in this 44-year-old volume.

Military Cryptanalytics, Part III

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/01/military-cryptanalytics-part-iii.html

The NSA has just declassified and released a redacted version of Military Cryptanalytics, Part III, by Lambros D. Callimahos, October 1977.

Parts I and II, by Lambros D. Callimahos and William F. Friedman, were released decades ago — I believe repeatedly, in increasingly unredacted form — and published by the late Wayne Griswold Barker’s Agean Park Press. I own them in hardcover.

Like Parts I and II, Part III is primarily concerned with pre-computer ciphers. At this point, the document only has historical interest. If there is any lesson for today, it’s that modern cryptanalysis is possible primarily because people make mistakes

The monograph took a while to become public. The cover page says that the initial FOIA request was made in July 2012: eight and a half years ago.

And there’s more books to come. Page 1 starts off:

This text constitutes the third of six basic texts on the science of cryptanalytics. The first two texts together have covered most of the necessary fundamentals of cryptanalytics; this and the remaining three texts will be devoted to more specialized and more advanced aspects of the science.

Presumably, volumes IV, V, and VI are still hidden inside the classified libraries of the NSA.

And from page ii:

Chapters IV-XI are revisions of seven of my monographs in the NSA Technical Literature Series, viz: Monograph No. 19, “The Cryptanalysis of Ciphertext and Plaintext Autokey Systems”; Monograph No. 20, “The Analysis of Systems Employing Long or Continuous Keys”; Monograph No. 21, “The Analysis of Cylindrical Cipher Devices and Strip Cipher Systems”; Monograph No. 22, “The Analysis of Systems Employing Geared Disk Cryptomechanisms”; Monograph No.23, “Fundamentals of Key Analysis”; Monograph No. 15, “An Introduction to Teleprinter Key Analysis”; and Monograph No. 18, “Ars Conjectandi: The Fundamentals of Cryptodiagnosis.”

This points to a whole series of still-classified monographs whose titles we do not even know.

EDITED TO ADD: I have been informed by a reliable source that Parts 4 through 6 were never completed. There may be fragments and notes, but no finished works.

Enigma Machine Recovered from the Baltic Sea

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/12/enigma-machine-recovered-from-the-baltic-sea.html

Neat story:

German divers searching the Baltic Sea for discarded fishing nets have stumbled upon a rare Enigma cipher machine used by the Nazi military during World War Two which they believe was thrown overboard from a scuttled submarine.

Thinking they had discovered a typewriter entangled in a net on the seabed of Gelting Bay, underwater archaeologist Florian Huber quickly realised the historical significance of the find.

EDITED TO ADD: Slashdot thread.