Trimethius didn't stop there - he suggested that cryptographers encipher messages by using the first row for the first letter, the second row for the second letter, and so on down the tableau. A cryptographer using the 10th row, for example, would encipher the plaintext letter "A" as "J." To encipher a letter, the cryptographer picks a row and uses the top row as the plaintext guide. It looks like this:Īs you can see, each row is a Caesar Shift. Each row shifted the alphabet another spot so that the final row began with "Z" and ended in "Y." You could read the alphabet normally by looking across the first row or down the first column. The next row used a Caesar Shift to move the alphabet over one space. The first row contained the alphabet as it is normally written. The matrix was 26 rows long and 26 columns wide. One such scholar was Johannes Trimethius, who proposed laying out the alphabet in a matrix, or tableau. Kings and priests hired scholars to come up with new ways to send secret messages. The Caesar Shift was too easy to crack - given enough time and patience, almost anyone could uncover the plaintext behind the ciphered text. The Renaissance was not only a period of intense creativity and learning, but also of intrigue, politics, warfare and deception.Ĭryptographers began to search for new ways to encipher messages. It wasn't until the Renaissance that cryptography again became popular. During this time, scholarship declined and cryptography suffered the same fate. The recipient of the message uses the proper technique, called the key, to decipher the message, changing it from a cipher back into a plaintext.Īfter the fall of the Roman Empire, the Western world entered what we now call the Dark Ages. The cryptographer converts the plaintext into a cipher and sends it on. The readable message is called the plaintext. In the next section, we'll look at a few of these more advanced methods of encryption.ĭeciphering the LanguageTo encipher a message means to replace the letters in the text with the replacement alphabet. Notice that the cipher alphabet wraps around to "A" after reaching "Z." Using this cipher system, you could encipher the phrase "How Stuff Works" as "KRZ VWXII ZRUNV."īoth of these systems, the Polybius Square and the Caesar Shift, formed the basis of many future cipher systems. You can visualize this code by writing the two alphabets on top of one another with the corresponding plaintext and cipher matching up like this: Plaintext For example, if you were to shift the English alphabet down three places, the letter "D" would represent the letter "A," while the letter "E" would mean "B" and so forth. He created enciphered messages by shifting the order of the alphabet by a certain number of letters. Julius Caesar invented another early cipher - one that was very simple and yet confounded his enemies. The cryptographer could make it even more difficult by mixing up the order of the letters instead of writing them out alphabetically. To encipher the phrase "How Stuff Works," the cryptographer would write "233452 4344452121 5234422543." Because he replaces each letter with two numbers, it's difficult for someone unfamiliar with the code to determine what this message means. Some people prefer to differentiate the words, using cryptology to refer to the science and cryptography to refer to the practice of secret writing.Ī cryptographer would write the letter "B" as "12". You Say Cryptology, I Say CryptographyIn English, the words cryptology and cryptography are often interchangeable - both refer to the science of secret writing. Today, even the amazingly complex encryption schemes common in Internet transactions may have a limited useful lifetime - quantum computing might make solving such difficult equations a snap. Cryptanalysts have proven these people wrong by relying on everything from the scientific method to a lucky guess. Throughout the history of cryptography, people who created codes or ciphers were often convinced their systems were unbreakable. What cryptographers create, cryptanalysts attempt to unravel. Cryptographers might use codes, ciphers or a combination of both to keep messages safe from others. These people are cryptanalysts, also known as code breakers.īinary code is the basis for many modern ciphers.Ī person who communicates through secret writing is called a cryptographer. On the other side of the information equation are people who use a combination of logic and intuition to uncover secret information. Nations, corporations and individuals protect secret information with encryption, using a variety of methods ranging from substituting one letter for another to using a complex algorithm to encrypt a message. This closeup shows some writings from the notebook of Enigma codebreaker Alan Turing, who played a major part in breaking codes during the Second World War.
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