1221 words - 5 pages

1. Introduction: What is Encryption?Encryption has become a necessity in modern society due to the nature of the information we must interact with everyday. Furthermore, the encryption of computer data is becoming increasingly important since much sensitive information is stored on our hard drives and human based codes are simply too easy for a computer to solve [1]. All forms of encryption are based on cryptology which is "the science of analyzing and deciphering codes and ciphers and cryptograms" [2]. Cryptology and simple codes have been used as early as the Roman Empire. The earliest encryption methods include using substitution ciphers and transposition ciphers which can be done using pen and paper [3]. However, encryption discussed on this essay refers to techniques employed by computers to conceal data.The idea behind encryption is that information is converted so that it cannot be read by a third party who is not involved with you or the party you are dealing with. All parties who wish to view this information would need a "key" to decipher the data to its original state [4]. The entire scheme is called a cryptosystem and is usually a collection of algorithms. The original information which needs to be secured is called plaintext. The "key" known as a cipher@ is an algorithm used to perform the encryption as well as the reverse, decryption. Finally the encrypted form of the text is known as ciphertext [3]. Modern computers generally use two types of encryptions. Symmetric-key encryption and public-key encryption. In non-technical usage, the words cipher and code are used synonymously. However, the two are two different concepts. Codes work at the level of words and phrases and encodes# itself by arranging the actual word. On the other hand, ciphers work at a lower level: the level of individual letters, small groups of letters or individual bits. Today the dominant technique used in cryptography is ciphers since codes have many disadvantages$[3].2. Symmetric-Key EncryptionSymmetric-algorithms are divided into stream ciphers and block ciphers. Stream ciphers take the information and encrypt them one bit at a time while block ciphers take a number of bits and encrypt them as a single unit [5]. Regardless of whether the encryption uses block ciphers or stream ciphers a symmetric-key encryption employs an identical key for both encryption and decryption [6]. How this works is that each computer will have a secret key that it uses to encrypt a packet of information before sending it over the network. Symmetric-key encryption requires both the receiving and sending computers to be identified so that the key can be installed in both. After the receiving computer receives the encrypted data, it uses the received key to decipher it to plaintext [7]. An example of a symmetric algorithm includes DES% and this form of cryptosystem is especially suited for transferring large data sets at a high rate [6]. The limitations of a symmetric-key encryption...

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