1476 words - 6 pages

Cryptography is the science of writing in secret code and is an ancient art. Cryptography has a long and fascinating history. Its use has been traced back to as early as 4000 years ago. Cryptography was used as a tool to protect national secrets and strategies. To understand the subject of cryptography, its history must also be explored. Cryptography exists in many different forms. There are many cryptographic algorithms. There are a numerous amounts of different types of cryptography. All these different types of cryptography have reasonable uses in the world. One key area where cryptography is used is in network security.

HISTORY & TYPES OF CRYPTOGRAPHY

The history of cryptography is outstanding. Cryptography has been dated back to 1900 B.C. when an Egyptian scribe used non-standard hieroglyphs in an inscription. Cryptography is the art of protecting information by transforming the data into an unreadable format. This is known as cipher text. The encrypted data can now only be deciphered, or decrypted by those who possess the secret key. A summary of this is that cryptography allows information to be transformed into a manner which the access to it can be limited by choice. Cryptography exists in many deferent forms. Various different kinds of cryptographic algorithms exist. There are several ways of classifying cryptographic algorithms.

SECRET KEY CRYPTOGRAPHY (SKC) – Uses a single key for both encryption and decryption

Secret Key Cryptography utilizes a single key for both encryption and decryption. The sender of the information uses the key to encrypt the plaintext and then sends the cipher text to the receiver of the information. The receiver must also have the same key to be able to apply it to the information and decrypt it to recover the plaintext. Due to the fact that only a single key is used for both encryption and decryption, Secret Key Cryptography is also known as Symmetric Encryption or a Symmetric Cipher.

SKC Algorithms Used Today: Some of the common SKC Algorithms in today’s use

• Data Encryption Standard (DES) – Most common SKC method used today. DES was originally designed by IBM in the 1970's. It was later adopted by the National Institute for Standards and Technology in 1977 for commercial and unclassified government applications.

• Advanced Encryption Standard (AES) – AES uses an SKC method using a block cipher designed by Belgian cryptographers. The algorithm uses a variable block length and key length. It allows any combination of keys lengths of 128, 192, or 256 bits and blocks of length 128, 192, or 256 bits.

• CAST-128/256 – Is a DES like substitution-permutation algorithm. It employs a 128-bit key operating on a 64-bit block. CAST-256 is an extension which uses a 128-bit block size and a variable length key. CAST-256 was one of the Round 1 algorithms in the AES process.

PUBLIC KEY CRYPTOGRAPH (PKC) – Uses one key for encryption and another for decryption

Public Key Cryptography has...

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