At their simplest, they are used by kids passing notes in class and at their most complex, by governments carrying out military operations. In between, they are used by people every time they pull out a credit card or shop online.
Codes substitute arbitrary symbols—typically, letters or numbers—for the components of the original message. Ciphers use algorithms to transform a message into an apparently random string of characters.
In “Codes and Ciphers,” a special topic course offered
recently by the mathematics department, students learn the difference and get an introduction to classical
and modern methods for encoding secret messages (cryptography) and the science of breaking codes and ciphers (cryptanalysis). It blends the history of secret writing, the art of creating codes, and the mathematics underlying the theory and practice of encryption and decryption.
“The puzzle nature of
the course really appeals to
students,” says Penelope Dunham, a research associate who offers the course. “Math majors and science majors love to solve puzzles.”
The course begins during the time of the Greeks and Romans with examples such as the Caesar cipher and proceeds all the way into the modern era. The Caesar cipher is a shift cipher, one of the simplest forms of encryption in which each letter of the message is replaced by a letter a certain number of positions down in the alphabet.
Some of the key moments in history that the class studies are the decoding of the Zimmerman Telegram in 1917 and the Allies’ successful cryptanalysis of Germany’s Enigma machine during World War II.
Intercepted and decoded by British intelligence, the Zimmerman Telegram was a secret diplomatic communication that proposed a military alliance of Germany, Mexico, and Japan in the event that the U.S. entered World War I. Its release inflamed U.S. public opinion and generated support for a declaration of war.
By World War II, the Germans were transmitting encrypted messages via the Enigma machine, but the British broke that as well. “Many students have seen the film The Imitation Game,” says Dunham, “but I think they’re still surprised to
learn just how important the
breaking of these codes has
been throughout history.”
“The students really enjoy the first half of the course because it’s stuff they can break,” says Dunham. “When we get to things like the Enigma machine and the computer era, the students can no longer break the ciphers, so then it becomes more about learning the mathematics
behind them.”
Today, thanks to the need
to send data securely online, cryptography is an unseen part
of everyday life, and students with the right math skills are in high demand.
“I’ve had two of my students go on to work for the National Security Agency, which is now one of the top employers of
math Ph.D.’s in the world,”
says Dunham.
Above is the key to solving the puzzle at the top of the page. Scroll down for the correct answer.
Sherlock
I have
found
you
Ciphers vs. Codes
Codes substitute arbitrary symbols—typically, letters or numbers—for the components of the original message. Ciphers use algorithms to transform a message into an apparently random string of characters.
Et Tu?
The Caesar cipher is a shift cipher, one of the simplest forms of encryption in which each letter of the message is replaced by a letter a certain number of positions down in the alphabet.
Reading List
For history, students read Simon Singh’s The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography, and for math, Dunham assigns Cryptological Mathematics, by R.E. Lewand.
The Code Talkers
The name is generally associated with Navajos who served with Marine divisions in the Pacific. The Iwo Jima landing, for example, was directed entirely by Navajo code. But code talking had been pioneered during World War I by Cherokee and Choctaw Indians.
FAQs
Diplomatic, military, and industrial secrets are often exchanged by disguising the information in a cryptogram—writing in cipher or code. Unlike the steganogram, a form of secret writing that involves concealment of the text itself, a message in cipher or code is transmitted openly. Only the meaning is hidden.
What are codes or ciphers with an example? ›
A code affects the word, and a cipher affects the individual letters. Cipher — A cipher is a system to make a word or message secret by changing or rearranging the letters in the message. Example: For example: A=G or A=&. Cryptology — Cryptology is the art and science of making and breaking codes.
Why do people use ciphers? ›
Ciphers are essential in preventing unauthorized access to sensitive data, thus providing a robust line of defense against cyber threats. Moreover, they enable secure communication over unsecured networks, allowing individuals and organizations to transmit data with confidence.
What is cipher test? ›
Ciphertext is encrypted text transformed from plaintext using an encryption algorithm. Ciphertext can't be read until it has been converted into plaintext (decrypted) with a key. The decryption cipher is an algorithm that transforms the ciphertext back into plaintext.
Why is it important to learn about codes? ›
It hones problem-solving and analysis skills, such as finding errors and thinking logically. Further, coding often helps people develop teamwork and interpersonal skills since software and application projects are often cross-disciplinary and collaborative.
Why is it important to use codes and standards? ›
Codes and standards establish minimum acceptable levels of safety, quality, and reliability. Understanding the codes and standards at both the industry and government level will allow you to better understand the expectations of your chosen field.
What do you call a person who deciphers codes? ›
These people are cryptanalysts, also known as code breakers. Carston Müller, SXC. Binary code is the basis for many modern ciphers. A person who communicates through secret writing is called a cryptographer. Cryptographers might use codes, ciphers or a combination of both to keep messages safe from others.
What are ciphers used for today? ›
The data output from either method is called the ciphertext. Modern ciphers enable private communication in many different networking protocols, including the Transport Layer Security (TLS) protocol and others that offer encryption of network traffic.
What is the most commonly used cipher? ›
The Caesar Shift is one of the most common and easiest ciphers to use, and is even still used today. It works by simply moving a set number of letters down the alphabet! Caesar's preferred amount was three letters to the left, making his name JULIUS become MXOLXV.
What is the goal of cipher? ›
In cryptography, a cipher is an algorithm or a set of mathematical instructions used to encrypt and decrypt data. The purpose of a cipher is to transform plaintext into ciphertext, which is the encrypted form of the original data.
Data encryption is a form of cryptography that converts plain text or data into a scrambled format known as ciphertext, making it unreadable to unauthorized users.
What is the difference between a code and a cipher? ›
Ciphers vs. Codes. Codes substitute arbitrary symbols—typically, letters or numbers—for the components of the original message. Ciphers use algorithms to transform a message into an apparently random string of characters.
What is the study of codes and ciphers? ›
The study of enciphering and encoding (on the sending end), and deciphering and decoding (on the receiving end) is called cryptography from the Greek κρυπτός (kryptos), or hidden and γράφειν (graphia), or writing. If you don't know Greek (and not many of us do) the above letters could be a form of code themselves!
What is a cipher example? ›
For example, "GOOD DOG" can be encrypted as "PLLX XLP" where "L" substitutes for "O", "P" for "G", and "X" for "D" in the message. Transposition of the letters "GOOD DOG" can result in "DGOGDOO". These simple ciphers and examples are easy to crack, even without plaintext-ciphertext pairs.
What is the importance of Cypher? ›
A cipher is a method used in cryptography for performing encryption or decryption. Essentially, it's a set of algorithms that you apply to your data (plaintext) to transform it into an unrecognizable form (ciphertext). This process helps to protect sensitive information from unauthorized access.
Why are secret codes important? ›
In more serious uses, codes and ciphers are used by our military and diplomatic forces to keep confidential information from unauthorized eyes.
Why is ciphertext important? ›
Ciphertext refers to data that is encrypted and unreadable. The only way to read encrypted data is by decrypting it using an encryption key. Since ciphertext can't be read without providing the encryption key, it's the best way to protect your sensitive data from prying eyes and unauthorized access.
