Ch 4 Encryption
4.1 Introduction
Cryptography is the common term given to the art and science of keeping the text messages secret. It is not the purpose to evaluate in detail any of the mathematical algorithms that are used in the cryptographic process, but instead to provide a general view of the process and its uses. To introduce briefly one of the fundamental building blocks of all network security, one must know the process of encryption and decryption. A process that transforms the given information (the plaintext) into a seemingly meaningless form (the ciphertext) using a mathematical algorithm and some secret information (the encryption key). The process of decryption revokes this transformation using a mathematical algorithm, in conjunction with some secret value (the decryption key) that reverses the effects of the encryption algorithm. An encryption algorithm and all its possible keys, plaintexts and cipher texts is known as a cryptosystem or cryptographic system. Figure 4 illustrates the process.
There are two main characteristics for cryptography:
1. It should be computationally infeasible to derive the plaintext from the cipher text without knowledge of the decryption key.
2. It should be computationally infeasible to derive the cipher text from the plaintext without knowledge of the encryption key.
Modern encryption systems are obtained from one of two basic systems: symmetric key (sometimes called shared key) systems, and asymmetric key (often called public key) systems. An encryption process the sender and receiver share a single and common key that is used to encrypt and decrypt the message, then is called as symmetric key systems. Symmetric-key systems are simpler and faster, but their main drawback is th...
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...stage, and compares with D-Shuffle sort in the next stage and the results are now compared and discussed below
The proposed new sorting method for secured message passing compares by Bubble sorting technique is achieved by 97.05% . The improvement reflects the efficiency and simplicity of direct substituition of sorting technique.
Figure 6. Comparison of Bubble sort based encryption with D-Shuffle sort
4.6 Conclusions
In the area of cryptography, a new idea has been incorporated with sorting technique to encrypt the text message for secured communication. This new study has involved a direct substitution, fast and secured message passing system. The fast and secured encryption is achieved by sorting algorithms which could increase the performance in transmission mechanism. This algorithm is based on the substitution techniques of classical encryption.
The sender would type the message in plaintext (not encrypted) and the letters would be illuminated on a glass screen. With the press of each typewriter key the rotor would shift 1/26 of a revolution giving each letter a different encryption each time, which made the code so difficult to crack. Due to the complexity of the code the enigma became very useful for the Germans for radioing messages to u-boats. The cipher was finally broken when the British were able to capture some key documents from a German warship.
What is encryption? Encryption is a technological technique that protects and secures the transfer of plain text information between two sources through the use of the internet. This is done by rearranging the text using a mathematical algorithm that renovates the message into an indecipherable form, which can only be unlocked and translated with a use of a key. The strength of the encryption key is measured by its length, which is determined by the number of bits and by the type of encryption program.
Asymmetric Key Encryption methods are DSA, Diffie Hellman, RSA, Elliptic Curve and DSA. Asymmetric Encryption
Alan Turing set up his machine in such way that it will look for the letter that Nazis are using to encrypt the phrase “Hail Hitler”. And by using the settings Alan Turing broke the Enigma code in less then 20 minutes by using his machine which he named “The Bomb Machine”.
PKC is the enabling technology for all Internet security and the increasing use of digital signatures, which are replacing traditional signatures in many contexts. However, RSA is better than PKC because RSA doesn’t need digital signature. As a result, the RSA algorithm turned out to be a perfect fit for the implementation of a practical public security system. In 1977, Martin Gardner first introduced the RSA system. After 5 years, company RSA used secure electronic security products. Nowadays many credit companies of all over the world use the RSA system or a similar system based on the RSA system.
During World War II, the German Nazis set off a boom in cryptanalysis by creating a revolutionary invention, known as, Enigma. The Enigma machine operated by having someone enter a message and then (using permutations) scramble it around with the use of three to five rotors. To encrypt a message for an Enigma with three-rotors, they used the following equation: ; with P being the plugboard transformation, U being the reflector, and L,M, and R being the left, middle, and right rotors. This scrambled message was then sent to a receiver who had to decipher the message by recreating the exact setting of the rotors from the sender's machine. However, the code, which has 158 quintillion different settings, was eventually broken by the Allies and used against the German Nazis as an advantage. And to show how confident the Germans were with this machine, until recently they still had no idea that the Allies had even cracked their code.
Data encryption refers to the process of transforming electronic information into a scrambled form that can only be read by someone who knows how to translate the code. In nowadays business world, it’s the easiest and most practical way to secure the information that we stored and processed, and it’s significant for our sensitive information. For example, as electronic commerce is popular now, the vendors and retailers must protect the customers’ personal information from hackers or competitors. They also have many business files or contracts that need to be strictly protected. Without data encryption, these important information may fall into wrong hands and be misused by others. Besides, data encryption may be used to secure sensitive information that exists on company networks, or create digital signatures, and help to authorize in business. No one should underestimate the importance of encryption. A little mistake in encryption may make sensitive information revealing, or even result in illegal and criminal accuse.
My knowledge has grown over the past six years, outwith the areas of learning offered by school courses, and I see this course as an opportunity to gain new skills and broaden my knowledge further. My main interests are varied, including communications and the internet, system analysis and design, software development, processors and low level machine studies. I have recently developed an interest in data encryption, hence my active participation in the RSA RC64 Secret-Key challenge, the latest international de-encryption contest from the RSA laboratories of America.
Sorting gained a lot of importance in computer sciences and its applications are in file systems, sequential and multiprocessing computing, and a core part of database systems. A number of sorting algorithms have been proposed with different time and space complexities. There is no one sorting algorithm that is best for each and every situation. Donald Knuth in [1] reports that “computer manufacturers of the 1960s estimated that more than 25 percent of the running time on their computers was spend on sorting, when all their customers were taken into account. In fact, there were many installations in which the task of sorting was responsible for more than half of the computing time.” Sorting is a significant concept whenever we study algorithms. Knuth divides the taxonomy of sorting...
Computer science is a vast field that includes nearly everything relating to computers. Everyday there is information transmitted all over the Internet. Pictures are uploaded, transactions are made on thousands of online retail websites, and banking transactions take place everyday on the Internet. All of these transactions have created a need for secure communications. People wish to keep things like banking, medical, and political information from the eyes of unwelcome parties. This has created a need for cryptography. Cryptography is the science or study of the techniques of secret writing, especially code and cipher systems, and is used by everyone from the average citizen to the government and military.
Data encryption refers to the transformation of data into a structure that makes it unreadable by anyone without a secret decryption key. It ensures that messages can be read only by the planned recipient. Encryption is the procedure of obscuring information to create it unreadable without special information. Only organizations and individuals with an abnormal need for secrecy have actually made good use of it. Nowadays, encryption is one of the most important technologies for maintaining your privacy and the security of important information. This helps out greatly especially when E-Commerce is being used.
The use of a cipher relies greatly on the use of an encryption key. The key may contain any auxiliary information added to the cipher to produce certain outputs.
In this era when the Internet provides essential communication between tens of millions of people and is being increasingly used as a tool for security becomes a tremendously important issue to deal with, So it is important to deal with it. There are many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting passwords. One essential aspect for secure communications is that of cryptography. But it is important to note that while cryptography is necessary for secure communications, it is not by itself sufficient. Cryptography is the science of writing in secret code and is an ancient art; In the old age people use to send encoded message which can be understand by the receiver only who know the symbolic and relative meaning of that encoded message .The first documented use of cryptography in writing dates back to circa 1900 B.C. Egyptian scribe used non-standard hieroglyphs in an inscription. After writing was invented cryptography appeared spontaneously with applications ranging from diplomatic missives to war-time battle plans. It is no surprise, then, that new forms of cryptography came soon after the widespread development of computer communications. In telecommunications and data cryptography is necessary when communicating in any untrusted medium, which includes any network, particularly the Internet [1].Within the context of any application-to-application communication, there are some security requirements, including:
...ults are obtained by taking average of 5 experiments. The proposed method is performing 96 % efficiency than Bubble sort and some random data set equivalence with Quick sort. The proposed algorithm D-Shuffle sort compares with some standard survey papers based on Divide & Conquer sorting methodology and its execution time results based on the various data size are given in the table 1. Based on the results in the table 1, for some larger data sets, the proposed algorithm works much faster than the GCS method.
Electronic Mail, a means of communication that is growing at a very rapid rate. In this paper, I will write about introduction of e-mail, the advantage and disadvantage of e-mail, mailing lists, sending an e-mail message, sending attachments, e-mail improvement, and security features. Introduction of Electronic Mail Electronic mail (E-mail) has become popular and easy way of communication in this decade. E-mail is a method of sending and receiving document or message from one person to another. E-mail is not only replacement for postal mail and telephones, and also it is a new medium. E-mail send plain text, images, audio, spreadsheets, computer programs can attach to an e-mail message. Using the e-mail, you must have a computer on a network. The computer must require a modem and phone line. Sending and receiving e-mail needs an e-mail program. Every e-mail user requires an e-mail address. This e-mail address is similar to a postal address. E-mail address is written as username@domain, for instance, PCLEE@juno.com. The username is used for sending and receiving e-mail.