Craig Bauer on unsolved ciphers

In 1953, a man was found dead from cyanide poisoning near the Philadelphia airport with a picture of a Nazi aircraft in his wallet. Taped to his abdomen was an enciphered message. In 1912, a book dealer named Wilfrid Voynich came into possession of an illuminated cipher manuscript once belonging to Emperor Rudolf II, who was obsessed with alchemy and the occult. Wartime codebreakers tried—and failed—to unlock the book’s secrets, and it remains an enigma to this day. In Unsolved, Craig Bauer examines these and other vexing ciphers yet to be cracked. Recently he took the time to answer some questions about his new book.

Why focus on unsolved ciphers?

They’re much more intriguing because they could be concealing anything. Some might reveal the identities of serial killers. Others could unmask spies, rewrite history, expose secret societies, or even give the location of buried treasure worth millions. This sense of mystery is very appealing to me.

Did you try to solve the ciphers yourself first?

There are so many unsolved ciphers that I realized I would never finish writing about them if I kept stopping to try to solve them. There’s one that I’m confident I could solve, but instead of doing so, I simply presented the approach I think will work and am leaving it for a reader to pursue. I expect that several of them will be solved by readers and I look forward to seeing their results!

Does someone who wants to attack these mysteries need to know a lot of mathematics or have computer programming skills?

No. Many of the ciphers were created by people with very little knowledge in either area. Also, past solvers of important ciphers have included amateurs. One of the Zodiac killer’s ciphers was solved by a high school history teacher. Some of the ciphers might be solved in a manner that completely bypasses mathematics. A reader may find a solution through papers the cipher’s creator left behind, perhaps in some library’s archives, in government storage, or in a relative’s possession. I think some may be solved by pursuing a paper trail or some other non-mathematical avenue. Of course, there are mathematical challenges as well, for those who have the skills to take them on. The puzzles span thousands of years, from ancient Egypt to today’s online community. Twentieth century challenges come from people as diverse as Richard Feynman (a world-class physicist) and Ricky McCormick (thought to have been illiterate).

Are all of the unsolved ciphers covered in the book?

No, far from it. There are enough unsolved ciphers to fill many volumes. I limited myself to only the most interesting examples, and still there were too many! I originally set out to write a book about half the size of what was ultimately published. The problem was that there was so much fascinating material that I had to go to 600 pages or experience the agony of omitting something fabulous. Also, unsolved ciphers from various eras are constantly coming to light, and new ones are created every year. I will likely return to the topic with a sequel covering the best of these.

Which cipher is your favorite?

I’m the most excited about the Paul Rubin case. It involves a cipher found taped to the abdomen of a teenage whiz-kid who was found dead in a ditch by the Philadelphia airport, way back in 1953. While I like well-known unsolved ciphers like the Voynich Manuscript and Kryptos, I have higher hopes for this one being solved because it hasn’t attracted any attention since the 1950s. The codebreakers have made a lot of progress since then, so it’s time to take another look and see what can be learned about this young man’s death. I felt it was very important to include cases that will be new even to those who have read a great deal about cryptology already and this is one such case.

Should the potential reader have some prior knowledge of the subject?

If he or she does, there will still be much that is new, but for those with no previous exposure to cryptology, everything is explained from the ground up. As a teenager I loved books at the popular level on a wide range of topics. In particular, the nonfiction of Isaac Asimov instilled in me a love for many subjects. He always started at the beginning, assuming his readers were smart, but new to the topic he was covering. This is the approach that I have taken. I hope that the book finds a wide readership among the young and inspires them in the same way Asimov inspired me.

Is there anything that especially qualifies you to write on this topic?

Early work on this book was supported by the National Security Agency through their Scholar-in-Residence program at the Center for Cryptologic History. They wanted me in this role because, while I have a PhD in mathematics and have carried out mathematical research in cryptology, I also have a passion for history and other disciplines. In fact, both of my books have the word “history” in their titles. The journal Cryptologia, for which I serve as the editor-in-chief, is devoted to all aspects of cryptology, mathematical, historical, pedagogical, etc. My love of diverse fields allows me to write with enthusiasm about ciphers in music, art, criminal cases, ancient history, and other areas. The broad approach to the subject is more entertaining and ensures that there’s something in the book for nearly every reader.

BauerCraig Bauer is professor of mathematics at York College of Pennsylvania. He is editor in chief of the journal Cryptologia, has served as a scholar in residence at the NSA’s Center for Cryptologic History, and is the author of Unsolved! The History and Mystery of the World’s Greatest Ciphers from Ancient Egypt to Online Secret Societies. He lives in York, Pennsylvania.

Craig Bauer: The Ongoing Mystery of Unsolved Ciphers (and new hope)

When a civilization first develops writing and few people are literate, simply putting a message down on paper can be all that is required to keep an enemy from understanding it. As literacy spreads, a more sophisticated method is needed, which is why codes and ciphers, a.k.a. “secret writing,” always follow closely on the heels of the discovery of writing. Over the millennia, ciphers have become extremely sophisticated, but so too have the techniques used by those attempting to break them.

In recent decades, everyone from mathematicians and computer scientists to artists and authors have created ciphers as challenges to specialists or the general public, to see if anyone is clever enough to unravel the secrets. Some, like the first three parts of James Sanborn’s sculpture Kryptos and the ciphers appearing in the television show Gravity Falls, have been solved, while others remain mysteries. The highly secretive online society known as Cicada 3301 has repeatedly issued such challenges as a means of talent scouting, though for what purpose such talented individuals are sought remains unknown. One unsolved cipher was laid down as a challenge by former British army intelligence officer Alexander d’Agapeyeff in his book Codes & Ciphers (1939). Sadly, when frustrated letters of enquiry reached the author, he admitted that he had forgotten how to solve it! Another was made by the famous composer Edward Elgar in 1897 as a riddle for a young lady friend of his. She, along with various experts, all failed to ferret out the meaning and Elgar himself refused to reveal it.


Elgar's cipher

Elgar’s cipher


Many unsolved ciphers appear in much more serious contexts. The serial killer who referred to himself as “The Zodiac” was responsible for at least five murders, as well as the creation of several ciphers sent to San Francisco newspapers. While the first of these ciphers was solved, others remain unbroken. Could a solution to one of these lead to an identification of the killer? Although many have speculated on his identity, it has never been firmly established. The Zodiac is not the only murderer to have left us such mysterious communiques, he is just the best known. Other killers’ secrets have persisted through relative obscurity. How many readers have heard of Henry Debsonys? In 1883, a jury sentenced him to death for the murder of his wife, after deliberating for only nine minutes. But this unfortunate woman was Henry’s third wife and the first two died under strange circumstances. Had Henry killed all of them? Will the ciphers he left behind confirm this? I think his ciphers will be among the first to fall this year, thanks to a major clue I provide in my book, Unsolved: The History and Mystery of the World’s Greatest Ciphers from Ancient Egypt to Online Secret Societies. There are many more such criminal ciphers. One deranged individual even sent threatening letters containing ciphers to John Walsh of America’s Most Wanted fame! The FBI’s codebreakers maintain a list of their top unsolved ciphers. At present, only two of these are known to the public, but many others that didn’t make the top 10 are available for anyone to try to crack.

How do codebreakers, whether amateur or professional, meet the challenges they face? Statistics and other areas of mathematics often help, as do computers, but two of the codebreakers’ most powerful tools are context and intuition. This is why ciphers have often been broken by amateurs with no programming skills and little knowledge of mathematics. Enter Donald Harden, a high school history teacher, who with assistance from his wife Bettye, broke one of the Zodiac killer’s ciphers by guessing that the egotistical killer’s message would begin with “I” and contain the word “KILL.” Context allows the attacker to guess words, sometimes entire phrases, that might appear in the message. These are known as cribs. During World War II, the German word eins (meaning one) appeared in so many Nazi messages that a process known as “einsing” was developed, searching the cipher for the appearance of this word in every possible position. In today’s ciphers, the word President appears frequently.

Of course, time and again cribs and intuition can lead in the wrong direction. Indeed, the single most important attribute for a codebreaker is patience. A good codebreaker will have the ability to work on a cipher for months, for that is sometimes what it takes to reach a solution, ignoring the body’s normal demands for food and sleep; during World War I, the French codebreaker Georges Painvin lost 33 pounds over three months while sitting at a desk breaking the German ADFGX and ADFGVX ciphers.

Fig 2

Fig 3Is it possible that some of the earliest known ciphers, dating from the ancient world, have survived unread by anyone other than those they were created for? I believe this is the case and that they’ve been hiding in plain sight, like the purloined letter in Poe’s classic tale. Those studying ancient cultures have long been aware of so-called “nonsense inscriptions.” These appear on Egyptian sarcophagi, Greek vases, runestones, and elsewhere. They are typically dismissed as the work of illiterates imitating writing, merely because the experts cannot read them. But all of these cultures are known to have made use of ciphers and some of the contexts of the inscriptions are so solemn (e.g. sarcophagi) that it’s hard to believe they could be meaningless. I’d like to see a closer examination of these important objects. I expect some of the messages will be read in the near future, if cryptologists can form collaborations with linguists. These two groups have worked together successfully in military contexts for many decades. It is time that they also join forces for historical studies.

With a very large number of unsolved ciphers, spanning millennia, having been composed by a diverse group of individuals, it seems likely that it will take a diverse group of attackers, with skills ranging over many disciplines, to solve them. Some mysterious texts may reveal themselves to clever computer programmers or linguists, others to those taking the psychological approach, getting into the creator’s head and guessing phrases he or she used in the cipher, and some may be broken by readers who manage to discover related material in government archives or private hands that provides just enough extra information to make the break. I look forward to seeing the results!

BauerCraig P. Bauer is professor of mathematics at York College of Pennsylvania. He is editor in chief of the journal Cryptologia, has served as a scholar in residence at the NSA’s Center for Cryptologic History, and is the author of Unsolved!: The History and Mystery of the World’s Greatest Ciphers from Ancient Egypt to Online Secret Societies. He lives in York, Pennsylvania.

Celebration of Science: A reading list

This Earth Day 2017, Princeton University Press is celebrating science in all its forms. From ecology to psychology, astronomy to earth sciences, we are proud to publish books at the highest standards of scholarship, bringing the best work of scientists to a global audience. We all benefit when scientists are given the space to conduct their research and push the boundaries of the human store of knowledge further. Read on for a list of essential reading from some of the esteemed scientists who have published with Princeton University Press.

The Usefulness of Useless Knowledge
Abraham Flexner and Robbert Dijkgraaf


The Serengeti Rules
Sean B. Carroll


Honeybee Democracy
Thomas D. Seeley


Silent Sparks
Sara Lewis


Where the River Flows
Sean W. Fleming


How to Clone a Mammoth
Beth Shapiro


The Future of the Brain
Gary Marcus & Jeremy Freeman


Searching for the Oldest Stars
Anna Frebel


Climate Shock
Gernot Wagner & Martin L. Weitzman


Welcome to the Universe
Neil DeGrasse Tyson, Michael A. Strauss, and J. Richard Gott


The New Ecology
Oswald J. Schmitz


Brian Kernighan on what we all need to know about computers

KernighanLaptops, tablets, cell phones, and smart watches: computers are inescapable. But even more are invisible, like those in appliances, cars, medical equipment, transportation systems, power grids, and weapons. We never see the myriad computers that quietly collect, share, and sometimes leak vast amounts of personal data about us, and often don’t consider the extent to which governments and companies increasingly monitor what we do. In Understanding the Digital World, Brian W. Kernighan explains, in clear terms, not only how computers and programming work, but also how computers influence our daily lives. Recently, Kernighan answered some questions about his new book.

Who is this book for? What kind of people are most likely to be interested?

BK: It’s a cliché, but it really is aimed at the proverbial “educated layman.” Everyone uses computers and phones for managing their lives and communicating with other people. So the book is for them. I do think that people who have some technical background will enjoy it, but will also find that it will help their less technical friends and family understand.

What’s the basic message of the book?

BK: Computers—laptops, desktops, tablets, phones, gadgets—are all around us. The Internet lets our computers communicate with us and with other computers all over the world. And there are billions of computers in infrastructure that we rely on without even realizing its existence. Computers and communications systems have changed our lives dramatically in the past couple of decades, and will continue to do so. So anyone who hopes to be at least somewhat informed ought to understand the basics of how such things work. One major concern has been the enormous increase in surveillance and a corresponding reduction in our personal privacy. We are under continuous monitoring by government agencies like the NSA in the United States and similar ones in other countries. At the same time, commercial interests track everything we do online and with our phones. Some of this is acceptable, but in my opinion, it’s gone way too far. It’s vital that we understand better what is being done and how to reduce the tracking and spying. The more we understand about how these systems work, the more we can defend ourselves, while still taking advantage of the many benefits they provide. For example, it’s quite possible to explore interesting and useful web sites without being continuously tracked. You don’t have to reveal everything about yourself to social networks. But you have to know something about how to set up some defenses. More generally, I’m trying to help the reader to reach a better than superficial understanding of how computers work, what software is and how it’s created, and how the Internet and the Web operate. Going just a little deeper into these is totally within the grasp of anyone. The more you know, the better off you will be; knowing even a little about these topics will put you ahead of the large majority of people, and will protect you from any number of foolish behaviors.

Can you give us an example of how to defend ourselves against tracking by web sites?

BK: Whenever you visit a web site, a record is made of your visit, often by dozens of systems that are collecting information that can be used for targeted advertising. It’s easy to reduce this kind of tracking by turning off third-party cookies and by installing some ad-blocking software. You can still use the primary site, but you don’t give away much if anything to the trackers, so the spread of information about you is more limited.

If I don’t care if companies know what sites I visit, why should I be worried?

BK: “I’ve got nothing to hide,” spoken by an individual, or “If you have nothing to hide, you have nothing to fear,” offered by a government, are pernicious ideas. They frame the discussion in such a way as to concede the point at the beginning. Of course you have nothing to hide. If that’s true, would you mind showing me your tax returns? How did you vote in the last election? What’s your salary? Could I have your social security number? Could you tell me who you’ve called in the past year? Of course not—most of your life is no one else’s business.

What’s the one thing that you would advise everyone to do right now to improve their online privacy and security?

BK: Just one thing? Learn more about how your computer and your phone work, how the Internet works, and how to use all of them wisely. But I would add some specific recommendations, all of which are easy and worthwhile. First, in your browser, install defensive extensions like like AdBlock and Ghostery, and turn off third-party cookies. This will take you less than ten minutes and will cut your exposure by at least a factor of ten. Second, make sure that your computer is backed up all the time; this protects you against hardware failure and your own mistakes (both of which are not uncommon), and also against ransomware (though that is much less a risk if you are alert and have turned on your defenses). Third, use different passwords for different sites; that way, if one account is compromised, others will not be. And don’t use your Facebook or Google account to log in to other sites; that increases your vulnerability and gives away information about you for minor convenience. Finally, be very wary about clicking on links in email that have even the faintest hint of something wrong. Phishing attacks are one of the most common ways that accounts are compromised and identities stolen.

KernighanBrian W. Kernighan is a professor in the Department of Computer Science at Princeton University. He is the coauthor of ten other books, including the computing classic The C Programming Language (Prentice Hall). He is the author of Understanding the Digital World: What You Need to Know about Computers, the Internet, Privacy, and Security.

David Alan Grier: The Light of Computation

by David Alan Grier

When one figure steps into the light, others can be seen in the reflected glow. The movie Hidden Figures has brought a little light to the contributions of NASA’s human computers. Women such as Katherine Goble Johnson and her colleagues of the West Area Computers supported the manned space program by doing hours of repetitive, detailed orbital calculations. These women were not the first mathematical workers to toil in the obscurity of organized scientific calculation. The history of organized computing groups can be traced back to the 17th century, when a French astronomer convinced three friends to help him calculate the date that Halley’s comet would return to view. Like Johnson, few human computers have received any recognition for their labors. For many, only their families appreciated the work that they did. For some, not even their closest relatives knew of their role in the scientific community.

GrierMy grandmother confessed her training as a human computer only at the very end of her life. At one dinner, she laid her fork on the table and expressed regret that she had never used calculus. Since none of us believed that she had gone to college, we dismissed the remark and moved the conversation in a different direction. Only after her passing did I find the college records that confirmed she had taken a degree in mathematics from the University of Michigan in 1921. The illumination from those records showed that she was not alone. Half of the twelve mathematics majors in her class were women. Five of those six had been employed as human computers or statistical clerks.

By 1921, organized human computing was fairly common in industrialized countries. The governments of the United States, Germany, France, Great Britain, Japan, and Russia supported groups that did calculations for nautical almanacs, national surveys, agricultural statistics, weapons testing, and weather prediction. The British Association for the Advancement of Science operated a computing group. So did the Harvard Observatory, Iowa State University, and the University of Indiana. One school, University College London, published a periodical for these groups, Tracts for Computers.

While many of these human computers were women, most were not. Computation was considered to be a form of clerical work, which was still a career dominated by men. However, human computers tended to be individuals who faced economic or social barriers to their careers. These barriers prevented them from becoming a scientist or engineer in spite of their talents. In the book When Computers Were Human, I characterized them as “Blacks, women, Irish, Jews and the merely poor.” One of the most prominent computing groups of the 20th century, the Mathematical Tables Project, hired only the impoverished. It operated during the Great Depression and recruited its 450 computers from New York City’s unemployment rolls.

During its 10 years of operations, the Math Tables Project toiled in obscurity. Only a few members of the scientific community recognized its contributions. Hans Bethe asked the group to do the calculations for a paper that he was writing in the physics of the sun. The engineer Philip Morse brought problems from his colleagues at MIT. The pioneering computer scientist John von Neumann asked the group to test a new mathematical optimization technique after he was unable to test it on the new ENIAC computer. However, most scientists maintained a distance between themselves and the Mathematical Tables Project. One member of the Academy of Science explained his reservations about the Project with an argument that came to be known as the Computational Syllogism. Scientists, he argued, are successful people. The poor, he asserted, are not successful. Therefore, he concluded, the poor cannot be scientists and hence should not be employed in computation.

Like the human computers of NASA, the Mathematical Tables Project had a brief moment in the spotlight. In 1964, the leader of the Project, Gertrude Blanch, received a Federal Woman’s Award from President Lyndon Johnson for her contributions to the United States Government. Yet, her light did not shine far enough to bring recognition to the 20 members of the Math Tables Project who published a book, later that year, on the methods of scientific computing. The volume became one of the most highly sold scientific books in history. Nonetheless, few people knew that it was written by former human computers.

The attention to Katherine Goble Johnson is welcome because it reminds us that science is a community endeavor. When we recognize the authors of scientific articles, or applaud the distinguished men and women who receive Nobel Prizes (or in the case of computer science, Turing Medals) we often fail to see the community members that were essential to the scientific work. At least in Hidden Figures, they receive a little of the reflected light.

David Alan Grier is the author of When Computers Were Human. He writes “Global Code” for Computer magazine and products the podcast “How We Manage Stuff.” He can be reached at