“Knot Forgotten: Unraveling the Inca Code”
 by Nick D’Alto
 
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The ancient Inca built an empire in South America as grand as ancient Rome. At its height, it was home to more than 10 million people, spread over 2,500 miles (4,023 km). Across their vast kingdom, the Inca transformed steep mountain slopes into terraced gardens. They constructed a highway system 25,000 miles long (40,233 km). End to end, these roads would stretch all the way around the Earth! This system included suspension bridges, some more than 150 feet long (46 meters). The Inca even built the spectacular cloud city of Machu Picchu, on a mountain peak 1.5 miles (2.4 km) above sea level. Yet when we read about the Inca today, we’re often told that they never developed a system of writing.

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Or did they? For years, scientists have wondered whether intricately knotted strings prepared by the Inca might act as a form of writing and preserve the history of this now once-powerful civilization. Could the knots in the strings represent letters, words, or numbers? Now, scientific codebreakers are examining these strings more closely. They are using modern computers, memories from Inca descendants, and old-fashioned detective work to unravel the Inca code. 

Knotted Strings

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The knotted strings are called khipu (pronounced KEY-poo). Manny Medrano is a PhD student at Harvard University in Massachusetts and an expert in this ancient form of communication. “Khipu simply means knot in the Andean language of Quechua,” he says. “The strings are sometimes referred to as talking knots.”

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“We know the knots on most khipu strings record numbers,” Medrano says. About a century ago, Leslie Leland Rock, a researcher from Columbia University in New York City, rediscovered how khipu knot math works.

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Each kind of knot stands for a different number. A knot tied like a figure-eight represents one, while the number of turns tied into larger knots signifies that number. “Above these knots,” Medrano says, “single knots mark the number of tens, hundreds, and thousands.” So khipu look something like an abacus1.

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Why so many numbers? The ancient Inca had to run an empire. “This was a vast civilization that generated vast amounts of data it needed to keep track of,” Medrano says. From precise census data for each town, to the contents of storehouses, tax records, and the numbers of fields and streams, the Inca kept track of their information. “It was all counted,” Medrano notes. “The Inca were outstanding data managers.”

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At the time, specially trained Inca scribes recorded all this information into the khipus, using the knot code. Then relay runners carried the coded messages along the road system, and back to the Inca capital. All this work was done to keep Inca rulers well informed. “The khipus made moving and storing data easy,” Medrano says, “much like our spreadsheets today.” Some have called the Inca system sort of a Bronze Age internet for coding and transporting data.

Gone With the Spanish

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That is, until this internet went dark. After the Spanish conquered the Inca empire in the 1530s, khipus remained in use for a time. Then the Spanish replaced them with their own record-keeping systems. They destroyed the khipus to break the Inca’s spirit, and in the process the secrets to deciphering them vanished, too. Today, most surviving khipus are preserved in museum collections.

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To better understand these objects, modern researchers are working to bring ancient Inca khipu into our age. They’ve created computerized databases in which they record the size, location, and other details about each knot on each string. A computer program can then search these “digital khipu” for repeating patterns—much the way human codebreakers try to break a code. 

“A Kind of Code”

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Evidence already suggests this code records more than just numbers. “According to Spanish chroniclers, the Inca claimed that the khipus could record the story of a person’s life, or of an entire people,” says Medrano. Now, modern research is beginning to confirm this idea and show that these knotted strings could hold the names of Inca people and places.

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Cracking “the Inca code” will require more effort. That’s partly due to its unique writing style. These knots that must be touched and counted are completely different from our own modern languages. Only braille2 might come close—and even that seems vastly different. Unraveling this lost way of writing could rewrite what we know about a lost civilization. It could let its people once again speak for themselves.

Unknotting History

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High in the Andes mountains in South America, a secret box hidden in an underground chamber beneath a small village church preserves an astonishing historical story. It contains information about a planned revolt by Inca villagers against their Spanish rulers in the 1780s. The tale is recounted in old Spanish letters, and remarkably, in colorful khipus as well. In 2015, Sabine Hyland became the first outsider ever allowed to see this treasure. She is an anthropology professor at the University of St. Andrews in Scotland and an authority on khipus.

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“These Inca were using khipu as a secret system of communications,” Hyland says. “One that the Spanish couldn’t read.” Hyland’s groundbreaking work is revealing that khipus are not just the museum relics once thought. “In some modern villages today,” she notes, “Inca elders wear ceremonial khipu handed down by their ancestors.”

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Sadly, no one alive in these villages today can still read these khipus. They are of a very special kind. So, what might the Collata khipus say? To find out, Hyland used two classic strategies from codebreaking. “The last part of a message is often a name, the way you would sign a letter,” she says. The other idea is called a rebus, which is a puzzle that mixes individual illustrations with letters. They are “like drawing a bee and a leaf to make the word belief,” she explains. “It’s making words by combining sounds.”

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By combining the Inca words for the colors of the last strings in the Collata khipus, Hyland was able to make a rebus that spells out the name of a leading Inca family connected to the 1780s uprising. This may be the first word read from an Inca khipu in centuries.

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“All languages change, so we can’t be certain that Inca before Spanish occupation used these methods, too,” Hyland says. “What we do have, is another proof of Inca genius and accomplishment.”

Excerpt from “Knot Forgotten: Unraveling the Inca Code” by Nick D’Alto from Muse. © Cricket Media, Inc. Reproduced with permission. All Cricket Media material is copyrighted by Cricket Media, Inc. and/or various authors and illustrators. Any commercial use or distribution of material without permission is strictly prohibited. Please visit http://www.cricketmedia.com/childrens-content-licensing for licensing and http://www.cricketmedia.com for subscriptions.

 
1abacus: an instrument for performing calculations by sliding counters along rods or in grooves
2braille: a writing system for the blind that uses letters and numbers made of raised dots
 

“The Enigma of Alan Turing”
 by the Central Intelligence Agency Newsroom
 
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Alan Turing—an English mathematician, logician, and cryptanalyst—was a computer pioneer. Often remembered for his contributions to the fields of artificial intelligence and modern computer science (before either even existed), Turing is probably best known for what is now dubbed the “Turing Test.” It is a process of testing a machine’s ability to “think.”

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The basic premise of the Turing Test is that a human judge would be placed in isolation and have two conversations—one with a computer and one with another person. The judge wouldn’t be told which was which. If the computer could fool the judge and carry on a conversation that is indistinguishable from that of the human, the computer is said to have passed the Turing Test. No computer has passed it yet.

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Less is known, however, about Turing’s intelligence work during WWII, when he used his mathematical and cryptologic skills to help break one of the most difficult of German ciphers, ENIGMA.

Codes and Ciphers

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Though often used interchangeably, the terms codes and ciphers are very different. A code changes the meaning of a word or phrase by replacing it with a different word or phrase to make a message secret. A cipher, on the other hand, makes a word or phrase secret by changing or rearranging the individual letters in a message. Together, codes and ciphers are called encryption.

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ENIGMA was a cipher machine. Each keystroke replaced a character in the message with another character determined by the machine’s rotor settings and wiring arrangements. These were previously established between the sender and the receiver. For additional security, the German military services usually double-encrypted their messages. They first substituted original text with code words and then enciphered the encoded text.

Breaking ENIGMA

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In the early years of WWII, Turing worked at Britain’s code breaking headquarters in Bletchley Park. In addition to mathematicians, Bletchley Park also recruited linguists and chess champions and attracted talent by approaching winners of a complex crossword puzzle tournament held by The Daily Telegraph.

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Turing’s mathematical and logic skills made him a natural cryptanalyst. Whereas cryptographers write encryption systems, and cryptologists study them, cryptanalysts like Turing break them. In 1939, Turing created a method called “the bombe,” an electromechanical device that could detect the settings for ENIGMA, allowing the Allied powers to decipher German encryptions. Turing and his colleagues were also able to break the more complicated Naval ENIGMA system. From 1941-1943, this helped the Allies avoid German U-boats during the Battle of the Atlantic.

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Poland was actually the first to realize that the solution to breaking ENIGMA would most likely be discovered by a mathematician. Polish cryptanalysts as early as 1932 could decode German ciphers. By 1939, they were able to successfully decipher messages written with an earlier version of ENIGMA using a replica machine like “the bombe” that could emulate the way ENIGMA worked. When Poland was overrun by Germany in September 1939, the Polish as well as French cryptanalysts shared what they knew about ENIGMA with the UK. This allowed the cryptanalysts at Bletchley Park, including Turing, to finally crack the ENIGMA ciphers.

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Once the German messages were decrypted, the British began supplying the Office of Strategic Services (OSS, precursor to CIA) with extensive information about foreign military espionage and sabotage activities. The most sensitive intelligence1 came from ULTRA—the code name applied to all intel coming from Bletchley Park, including the intercepts of German military messages sent with the ENIGMA machine. Because of the volume of the traffic, the British insisted that the OSS set up a separate, extra-secure component to handle the material.

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On March 1, 1943, OSS Director William J. Donovan created the Counterintelligence Division in the Secret Intelligence Branch. It was the first centralized, national-level counterintelligence office in US intelligence history and the predecessor of CIA’s Counterintelligence Staff and Counterintelligence Center.

Recognition of Alan Turing

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Turing’s work at Bletchley Park was vital in ending the war. General Dwight D. Eisenhower told the British intelligence chief in July 1945 that ULTRA, “saved thousands of British and American lives and, in no small way, contributed to the speed with which the enemy was routed and eventually agreed to surrender.”

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Nevertheless, Turing would spend the majority of his career focused on what would eventually become modern day computing. He was posted to serve with the US Navy’s Cryptanalytic Section for several months in 1943. There, he met and discussed mathematical models of communication and computation with Claude Shannon (the father of information theory). To this day, our communications networks are built on top of Shannon’s ideas, while our computing devices, processors, and chips are built upon Turing’s ideas. Turing’s contribution to modern computing was so significant that the prestigious A.M. Turing Award—sometimes known as the “Nobel Prize” of Computer Science—is named after him.

Excerpt from “The Enigma of Alan Turing” by the Central Intelligence Agency Newsroom. https://www.cia.gov/stories/story/the-enigma-of-alan-turing/ (9/14/23). Public domain.
 
1intelligence: information of military or political value
 

‎Question
PART 2 – Writing Prompt
You have read two texts about efforts to understand codes and ciphers. Based on the information in the texts, what skills are important for creating and breaking codes and ciphers? Write an informational essay explaining these skills and how they help researchers, cryptographers, and cryptanalysts in their work. Develop your essay using clear and relevant evidence from both texts.

Manage your time carefully so that you can

plan your response and do some prewriting
type your essay
Be sure to

use evidence from both texts
avoid over-relying on one text
Your response should be in the form of a multi-paragraph, informational essay.

Enter your response in the space provided.