The History and Mathematics of Codes and Code Breaking

Author: jackso92

Blindly Building

The most interesting passage from Cryptonomicon that relates to a discussion earlier in the course is found on page 89. Here, Lawrence describes the most intriguing machine found at Station Hypo: at machine built by Commander Schoen and designed to break Japan’s INDIGO cipher. According to the book’s description, INDIGO was similar to ENIGMA, in that it was enciphered using a machine. However, unlike ENIGMA, none of the cryptanalysts had seen the INDIGO machine, so they had no idea how to tackle it. Amazingly, Schoen was able to reverse-engineer the cipher machine simply by analyzing the encoded messages and finding patterns in the numbers.

Of course, this section directly relates to our discussion of ENIGMA and its downfall. The main difference between the two, though, seems to be where the bulk of the security was. With ENIGMA, cryptanalysts struggled to break the code, even with the machine in front of them. According to the book, the major breakthrough with INDIGO was creating a copy of the machine.

After reading the passage, I was convinced that Stephenson had fabricated this part of the story. I found it highly unlikely that any person could reverse-engineer an elaborate mechanism by simply searching for patterns in encrypted knowledge. However, after a quick Wikipedia search, I found that this instance was actually based off of a real-life occurrence.

The actual cipher was named PURPLE (INDIGO was a great name for Stephenson to pick) and the main storyline remains the same: a machine was being used to encipher messages and no one knew what it looked like. The biggest difference between reality and the fictionalized story is that multiple people worked together to create the PURPLE machine, compared to the lone Commander Schoen in Cryptonomicon. Nevertheless, creating a complex machine by analyzing the numbers it output is still genius.

Image: “COBOL Rube Goldberg” by Phil Manker

The Availability of Ingenuity

I’m a staunch supporter of sharing information. In fact, I believe that patents should have a quicker expiration date (especially in fields where innovation moves very rapidly). Consider this: a patent filed in 1993 for a particular style of trackball mouse would still be in effect until next year. However, the vast majority of us do not utilize such hardware anymore.

What does this have to do with the NSA restricting the strength of encryption available to businesses? Without equal access to innovations and information, there is a lag between discovery and improvements. If everyone has equal access to information, there is a greater chance that breakthrough ideas will emerge. This simple principle is demonstrated by Singh’s description of the development of our modern encryption techniques. Because information was shared among different groups, a team tackled one security problem (key distribution) while another group on the other side of the United States worked on another issue (one-way encryption functions).

by Nick CarterBeyond this fact, there is the consideration that the NSA was effectively lying to the public about security. The NSA wanted to promote DES as a universal standard of secure communication. However, they made provisions to keep it from being as secure as it could be. In effect, the NSA was convincing businesses that DES offered adequate protection of corporate secrets. This sort of repression of information brings to mind “Big Brother” and “doublethink” in a realization of George Orwell’s intrusive government.

I can see no rationale adequate enough to justify the NSA’s paranoia. Their attempt to keep  the public’s secrets under their thumb was a bad idea.

Photo: Broken Rusty Lock by Nick Carter

Privacy for the Sake of Privacy

The passage in the book that I found most interesting comes from Chapter 4. Marcus discusses what it feels like to be locked up with all his privacy revoked. I often wondered why it matters so much that we keep our lives private. If we are doing nothing wrong, why try to keep a secret. For example, I have a friend who refuses to use Google because of their tendency to keep information regarding users.

In this passage, Doctorow relates privacy to something we all can understand: using the bathroom. He proclaims that there is nothing inherently wrong with using the bathroom, but we would never volunteer to do so while others were watching. In regards to personal data and using the bathroom, he feels: “It’s not about doing something shameful. It’s about doing something  private. It’s about your life belonging to you.”

 I realized that having nothing to hide is not the same thing as putting your life on blast. I could also better understand Marcus’s plight in his fight for privacy after reading the comparison. As an adamant technology adopter, I know how intruding services can be, but there is also a trade-off. In the case of Google, allowing its servers to hold your data means better search results. I think the main question we must ask ourselves is: Is the trade-off worth the breach in privacy?

Image: Glass House by James Vaughan

The Beale Ciphers Continue to “Puzzle” Cryptanalysts

The Beale Ciphers remain tantalizing to this day for two main reasons. First, the magnitude of the reward is impressive. $20 million is a lot more money than the average American will see in his or her lifetime. Coming into such a sum by simply solving a puzzle seems ridiculous.

Which leads to the next reason: because the Beale Ciphers are “simply” puzzles, it stands to reason that a person may have some insight that none of the previous cryptanalysts have had. There is a chance that any individual, professional or amateur, may stumble upon the correct answer. Because stories such as these are impressive, history has preserved them, which feeds our belief that we could be the next such lucky individual.

 Image: “Puzzled,” by Mykl Roventine

The Great Headache

The Great Cipher used by King Louis XIV was an extremely strong cipher for several reasons. First, the cipher text included 587 different numbers. This magnitude of possible decipherments was the first line of defense. Additionally, because multiple cipher types had been created by the time the Great Cipher was implemented, there were many more possibilities for the encryption than just the simple monoalphabetic cipher. However, the Rossignols chose not to use any previously created ciphers, vouching instead to devise their own. This creativity further complicated the matter of decipherment. Because the Great Cipher substituted numbers for syllables, any letter-based frequency analysis was useless. This major difference was probably the biggest reason why the cipher stayed unbroken for so long. Once discovering the substitution for syllables, the hard work of decipherment was still far from completion. The next stumbling block came in the form of inconsistency. Some of the numbers stood not for syllables, but for individual letters. Finally, the Rossignols laid “traps”, as Singh refers to them, within the cipher itself. One such example is a number which deletes the previous number. Combining all the individual parts of the Great Cipher results in a code which is devilishly difficult to decipher. Considering all the intricacies of the Great Cipher, it is little wonder that it remained a mystery for two centuries.

Cryptography and the Availability of Information

I think that amateur cryptanalysts using methods that were impossible for some early civilizations to use demonstrates the accessibility and ubiquity of information today. For example, some puzzles are centered around ciphers and decryption. These puzzles attract the attention of novices who have little to no experience in cryptanalysis. Never the less, these amateurs utilize strategies such as frequency analysis and recognition of small or common words (a, the, and) without having ever studied them. Even on our first day of class, we were able to decrypt the cipher text presented to us by using some of these methods. Similarly, we perform other “higher-order” thinking tasks on a daily basis without giving much thought. We type rapidly, blaze the internet, estimate sale prices, and navigate Vanderbilt with (relative) ease. Of course, we utilize technology to make many of these tasks much easier, but we also must know how to use the technology and make it work for us. Thirty years ago, only serious business people and others with special training used computers. Today, most of us carry around a “tiny computer” with us at all times and know how to operate it efficiently. Basically, we do many things today that require skills that we take for granted. At the dawn of cryptanalysis, however, this knowledge simply was not there for all to benefit from. The moral of the story: when your first [insert impossible class name here] test score comes back much, much lower than you had hoped, take pride in knowing that in the Middle Ages, you would be hailed as a genius.

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