An Encryption and Decryption Algorithm for Messages Transmitted by Phonetic Alphabets

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  • Topic: Cryptography, Encryption, Cipher
  • Pages : 8 (2463 words )
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  • Published : December 2, 2008
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The algorithm pertains to creation of a middle level message transmission mechanism between the highly sophisticated encryption technique and the messages transmitted by phonetic alphabet codes. The algorithm suggests two levels in the language with each level varying in complexity and advantages. Keywords: Complexity, grammar, language, phonetic, regular expression. Technique used now: The alphabet is used to spell out parts of a message containing letters and numbers to avoid confusion, because many letters sound similar, for instance "n" and "m" or "b" and "d". For instance the message "proceed to map grid DH98" could be transmitted as "proceed to map grid Delta-Hotel-Niner-Ait". [3] Using "Delta" instead of "D" avoids confusion between "BH98" and "DH98".

In addition to the traditional military usage, civilian industry uses the alphabet to combat similar problems in the transmission of messages over telephone systems. For example, it is often used in the retail industry where customer or site details are spoken over the telephone (in order to authorize a credit agreement or confirming stock codes), although ad hoc coding is often used in that instance. It has found heavy usage in the information technology industry to accurately and quickly communicate serial/reference codes (which can be and are frequently extremely long) or other specialized information by voice. Examples: Several letter codes and abbreviations using the phonetic alphabet have become well-known, such as Bravo Zulu (letter code BZ) for "well done"[2], Checkpoint Charlie (Checkpoint C) in Berlin, and Zulu Time for Greenwich Mean Time. Need: Today with increased scales, volumes and complexities of communication several agencies use this technique of communication. This has led to

increasing of probabilities of confusion and trespassing in the messages of particular agencies. There are several encryption and decryption techniques available for messages to be transmitted. However there is absence of any technique focused exclusively on needs and characteristics of messages transmitted through phonetic language. Existing Solutions: The techniques for data encryption have been in existence for the last several thousand years. The earliest reference of their use is attributed to Spartan generals [5] who used it to send across secret messages. All such techniques can be divided into two broad categories on basis of their implementation methodology. [6] Cipher technique along with all its variants belongs to the category of techniques which can be implemented by senders manually. The tasks can be done in absence of computers and other sophisticated machinery as well. The other class of techniques is more secure but needs elaborate computational proceedings and machinery to be implemented. Such limitation makes those techniques though stronger unviable for messages transmitted though phonetic alphabets. Phonetic messages are sent directly from the field and require manual yet strong encryption techniques. We are analyzing only cipher techniques as other complex techniques are unviable for the setup. Cipher technique [7]

A cipher is used to encrypt and decrypt the messages. It consists of three components: (1) the encryption algorithm, (2) the decryption algorithm and (3) the key expansion algorithm (also known as key scheduling or key setup). The key expansion algorithm expands the user key or cipher key to a larger intermediate key, to allow (ideally) all bits of the cipher key to influence every round of the encryption algorithm. There are several kinds of ciphers. Caesar Cipher [8]

In this each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. For example, with a shift of 3, A would be replaced by D, B would become E, and so on. The method is named after Julius Caesar, who used it to communicate with his generals. Substitution Cipher [9]

It is a method of encryption by which...
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