Cryptography Essay ⋆ Political Science Essay Examples ⋆ EssayEmpire

This example Cryptography Essay is published for educational and informational purposes only. If you need a custom essay or research paper on this topic please use our writing services. EssayEmpire.com offers reliable custom essay writing services that can help you to receive high grades and impress your professors with the quality of each essay or research paper you hand in.

Cryptography, from the Greek krupto-, meaning “to conceal,” and grapho-, meaning “to write,” is the science of concealed writing; it is a technical term referring to the translation of messages into ciphers or codes. Cryptology is the study of both cryptography and cryptanalysis. Cryptanalysis is the science of decrypting ciphers and codes without a key. Within modern cryptology, there are many theories and practices, particularly focusing on the basic infrastructure used in cryptographic systems.

The fundamental intention of cryptography is to enable two individuals, normally called “Alice” and “Bob,” to communicate information securely. “Oscar” is the potential third-party adversary who wants to intercept the message.

A general model of a cryptosystem can be visualized as follows: Alice wants to communicate a plaintext message to Bob. She ciphers the plaintext message using a key according to the encryption rule of the system. Bob receives the cipher text, which can also be received by Oscar, who can be either a passive observer intending to gain the key for reading all the communication messages or an adversary intending to impersonate the original messenger and to modify the message to the receiver. Cryptosystems are intended so only Bob is able to decode (decrypt) the cipher text because he possesses the key that reconstructs the message into plaintext, thereby preventing Oscar from receiving any information from the message. The difference between enciphering and encoding is enciphering requires each letter (or numeral) of a message to be replaced by another letter (or numeral), whereas encoding replaces entire sentences, syllables, or words. The code is the predetermined rules for converting the messages from one representation to another. A cryptosystem using an encryption key for message communication is specified by a five tuple representing P, C, K, E, and D. P is a finite set of every possible plaintext; C is a finite set of every possible cipher text; K is a finite set of every possible key; E is the space of the encryption rule; D is the space of the decryption rule; therefore, k ∈K, eK: P → C. Conversely, each k ∈K and each x ∈ P contain a dK, such that dK(eK(x)) = x for all plaintexts x.

The antiquity of cryptology is well attested in the history of civilization. The beautiful hieroglyphic script of ancient Egypt, for instance, would have been impossible to decipher without discovery of the Rosetta stone by French soldiers in 1799. The Spartans used a cryptographic device called a scytale, wherein a sheet of papyrus with a message relating to their military campaign was wound around a cylinder; to read the cipher, the recipient had to possess a staff of the same diameter on which the papyrus could be unwound. The Greek historian Polybius created a 5 × 5 grid using the twenty-four letters of the Greek alphabet, known as the Polybius square. During World War I (1914–1918), the Germans used the ADFGX cipher for communication. The German cipher used a 6 × 6 grid based on the Polybius square. The cipher of Julius Caesar encrypted messages in a rotated alphabet that used a shift of three letters to the immediate right. In the New Testament, the name Babylon was sometimes used as a designation for Rome. Jewish literature equated Edom, Egypt, Kittim, and Rome with Babylon as a type of cipher.

Ancient ciphers and codes, however, were much more simplistic than those of the computer age. Crypotological progress was essentially halted between the decline of the Roman Empire and the rise of Islam. Cryptanalysis among Arabs was pioneered in the eighth century and subsequently continued. The necessity of mathematical advances, which had not yet occurred, meant that cryptology would not be developed further until late in medieval history. In 1412, Arabic knowledge of cryptology was described in the Subh al-Asha, the classical fourteen-volume encyclopedia, with tremendous detail. Francis Bacon developed a biliteral alphabet, known as the bilateral cipher, in his De Augmentis Scientiarum (1624) using the two characters, a and b, in groups of five letters. Edgar Allan Poe, in his 1843 short story, “The Gold Bug,” popularized cryptanalysis with a detailed description of methodology to decipher any monoalphabetic substitution cipher. Additional development in cryptology occurred in harmony with the emergence of modern armies and intelligence services throughout the nineteenth century. The end of the world wars and invention of the computer advanced cryptology even further. The ciphers and codes of the present age are so advanced that it is impossible to decode them without the combination of both human ingenuity and computer proficiency.

Bibliography:

Beutelspacher, Albrecht. Cryptology: An Introduction to the Art and Science of Enciphering, Encrypting, Concealing, Hiding, and Safeguarding Described without Any Arcane Skullduggery but Not Without Cunning Waggery for the Delectation and Instruction of the General Public. Washington, D.C.: Mathematical Association of America, 1994.
Deavors, Cipher A., and Kruh, Louis. Machine Cryptography and Modern Cryptanalysis. Dedham, Mass.: Artech House, 1985.
Denning, Dorothy Elizabeth Robling. Cryptography and Data Security. Reading, Mass.: Addison-Wesley, 1982.
Gaines, Helen F. Cryptanalysis: A Study of Ciphers and Their Solution. New York: Dover, 1956.
Kahn, David. The Codebreakers, rev. ed. New York: Scribner, 1999.
Konheim, Alan G. Cryptography: A Primer. New York:Wiley, 1981.
Menezes, Alfred J., Paul C. van Oorschot, and Scott A.Vanstone. Handbook of Applied Cryptography. Boca Raton, Fla.: CRC Press, 1996.
Singh, Simon. The Code Book:The Science of Secrecy from Ancient Egypt to Quantum Cryptography. London: Fourth Estate, 1999.
Van der Lubbe, Jan C. A. Basic Methods of Cryptography, translated by Steve Gee. New York: Cambridge University Press, 1998.
Wolfe, James Raymond. Secret Writing: The Craft of the Cryptographer. New York: McGraw-Hill, 1970.