Classical encryption techniques raj jain washington university in saint louis saint louis, mo 63. Classical encryption techniques in cryptography and network security free download as powerpoint presentation. Classical encryption techniques washington university. Secret key ciphers use a secret key for encryption. Cryptanalysis of monoalphabetic the relative frequencies of the letters in the. It explains how programmers and network professionals can use cryptography to maintain the privacy of computer data. To introduce the rudiments of the vocabulary of computer and network security and that of encryptiondecryption. Chapter 2 classical encryption techniques flashcards quizlet. Chapter 2 classical encryption techniques flashcards. These chips are widely available and incorporated into a number of products. Two building blocks of all classical encryption techniques are substitution and transposition.
Symmetric key encryption algorithm uses same cryptographic keys for both. Fully homomorphic encryption without modulus switching. Such a scheme is known as a cryptographic system cryptosystem or a cipher. Classical encryption techniques there are two requirements for secure use of conventional encryption. It takes the ciphertext and the secret key and produces the original plaintext. Integrating classical encryption with modern technique. Fully homomorphic encryption without modulus switching from classical gapsvp.
Privatekey encryption algorithms a privatekey or secretkey, or singlekey encryption algorithm is one where the sender and the recipient share a common, or closely related, key all traditional encryption algorithms are privatekey overview of a privatekey encryption system and attacker 912010 classical cryptography. A symmetric encryption scheme has five ingredients. This tutorial covers the basics of the science of cryptography. Only those who possess secret key can decipher decrypt the message into plain text. Substitutionreplace one element in plaintext with another transpositionrearrange elements product systemsmultiple stages of substitutions and transpositions number of keys used. Introduction to finite fields and their applications pdf. Cryptograph y and network security seventh edition by william stallings chapter 3 classical. Chapter 2 classical encryption techniques symmetric encryption, also referred to as conventional encryption or singlekey encryption, was the only type of encryption in use prior to the development of publickey encryption in the 1970s. Request pdf analysis of classical encryption techniques in cloud computing cloud computing has become a significant computing model in the it industry. Loai tawalbeh fall 2005 basic terminology plaintext the original message ciphertext the coded message. Classical encryption techniques linkedin slideshare. The secret key is also input to the encryption algorithm.
Symmetric encryption, also referred to as conventional encryption or singlekey encryption, was the only type of encryption in use prior to the development of publickey encryption1. Pdf comparing classical encryption with modern techniques. Nov 07, 2016 lecture slides by lawrie brown for cryptography and network security, 5e, by william stallings, chapter 2 classical encryption techniques. Classical cryptography and quantum cryptography geeksforgeeks.
Cryptanalysis the process of attempting to discover x or k or both is known as cryptanalysis. Pis a finite set of possible plaintexts cis a finite set of possible ciphertexts k, the keyspace, is a finite set of possible keys e is a finite set of encryption functions. It is the hash function that generates the hash code, which helps. Classical encryption techniques in network security. Classical encryption techniques in cryptography and network. Analytical study on encryption techniques and challenges in. A stream cipher processes the input elements continuously, producing output element one at a time, as it goes along. Loai tawalbeh computer engineering department jordan university of science and technology jordan cpe 542. Classical and modern encryption techniques are investigated and then compared here. Another way of classifying cryptographic algorithm are mono alphabetic cipher and poly alphabetic cipher 22 based on the mapping of plain text alphabet to cipher text alphabet. Analysis of classical encryption techniques in cloud. Comparing classical encryption with modern techniques. Cipher algorithm for transforming plaintext to ciphertext. Almost all secret key ciphers are essentially a combination of two simple techniques.
With the use of symmetric encryption, the principal security problem is maintaining the secrecy of the key. Classical encryption techniques cryptography cipher. Classical cryptography has two types of techniques. The encryption takes m successive plaintext letter and substitutes them for m ciphertext letters. Starting with the origins of cryptography, it moves on to explain cryptosystems, various traditional and modern ciphers. Sep 16, 20 classical encryption techniques in network security 1. A general paradigm for algorithm design threestep process.
This approach is also called as posteriori approach. Classical encryption techniques symmetric cipher model. In general, though, n is set to 64 or multiples thereof. Public key encryption algorithm uses pair of keys, one of which is a secret key and one of which is public. If we look at the figure below we can better understand. This allows the sharing of electronic information and resources. A symmetric encryption scheme has five ingredients as shown in the following figure. Discovering the algorithm that performs better for large as well as for small instances is critical. K d c ek e, p p dk d, ek e, p keyless cipher a cipher that does not require the use of a key key cannot be changed if the encryption algorithm should fall into the interceptor s hands, future messages can still be kept secret because the. Substitution the letters of plaintext are replaced by other letters or by numbers or symbols.
The many schemes available today for encryption and decryption. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Of the plaintext is viewed as a sequence of bits, then substitution involves replacing plaintext bit patterns with ciphertext bit patterns 2. Bruteforce attack try every key to decipher the ciphertext. Classical techniques symmetric model substitution transposition rotor machines steganography characterising cryptographic systems operations used for encryption. Mar 01, 20 plaintext encrypted two letters at a time. Communication encrypts as com x munication if the letters appear on the same row of your table, replace them with the letters to their immediate right respectively wrapping around to the left side of the row if a letter in the original pair was on the right side of the row. The us national bureau of standards nbs declared it in 1976 the standard for us government cryptography, for documents that are sensitive but not classi. With the message x and the encryption key k as input, the encryption algorithm forms the ciphertext y y1, y2. It remains by far the most widely used of the two types of encryption. Classical encryption techniques computer science and. Some basic vocabulary of computer and network security and a.
The process of protecting information by transforming encrypting it into an unreadable format is called cryptography. In case m 3, the encryption can be expressed in terms of the matrix multiplication as follows. Cryptography and network security for computers and email. Classical encryption techniques developed lowcost chip implementations of data encryption algorithms. This is essentially the encryption algorithm run in reverse. In the symmetric cryptography a single key is used for encrypting and decryption the data. Disadvantages practical consideration may force us to test algorithm for small number of instances. Classical encryption techniques as opposed to modern cryptography symmetrickey. Classical encryption techniques jordan university of. In terms of security, hashing is a technique used to encrypt data and generate unpredictable hash values. It uses encryption algorithm to generate ciphertext that can only be read if decrypted. Building blocks of classical encryption techniques. Network security classical encryption techniques 2.
Pis a finite set of possible plaintexts cis a finite set of possible ciphertexts k, the keyspace, is a finite set of possible keys e. This is my implementation for some classical encryption techniques. Classical encryption techniques lecture notes on computer and network security. A substitution technique is one in which the words or text of plaintext are replaced by other letters or by numbers or symbols.
The national security agency nsa is responsible for higher levels of security. This is the original intelligible message or data that is fed into the algorithm as input. Chosen plaintext attacker selects plaintext and gets ciphertext chosen international it university is 09 spring 2017 lecture 2. Classical encryption techniques in cryptography and network security. Sender and receiver must have obtained copies of the secret key in a secure fashion and must keep the key secure. Mar 09, 2015 in classical cryptography, the various parameters used by a decryption algorithm are derived from the same secret key that was used in the encryption algorithm. Thisgeneralideaisillustrated in figure 1 for the case of n 4. Given the algorithm and ciphertext, an attacker cannot obtain the key or plaintext. In a modern block cipher but still using a classical encryption method, we replace a block of n bits from the plaintext with a blockofnbitsfromtheciphertext. These two keys are mathematically linked with each other. There are two types of encryptions schemes as listed below. The many schemes used for encryption constitute the area of study known as cryptography.
Techniques used for deciphering a message without any knowledge of the enciphering details fall into the area of cryptanalysis. If a pair is a repeated letter, insert a filler like x, ex. Analytical study on encryption techniques and challenges. Encryption is a security method in which information is encoded in such a way that only authorized user can read it. Starting with algebraic equations, this paper touches on how finite fields work and how they can be used in everyday life. Playfair cipher one approach to improve security was to encrypt multiple letters the playfair cipher is an example invented by charles wheatstone in 1854, but named after his friend baron playfair. This is the limitation of this encryption technique that this private key must be distributed only among the authorized sender and receiver. On average, need to try half of all possible keys time needed proportional to size of key space. Classical encryption techniques in network security 1. We can write this as y ekx this notation indicates that y is produced by using encryption algorithm e as a function of the plaintext x, with the specific function determined by the value of the key k. Substitution means replacing an element of the plaintext with an element of cipher text.
The internet is a worldwide network of connected computers. The encryption algorithm performs various substitutions and transformations on the plaintext. Symmetric encryption, also referred to as conventional encryption or singlekey encryption, was the only type of encryption in use prior to the development of publickey encryption in the 1970s. Replace characters of plaintext by other characters. Classical encryption techniques free download as powerpoint presentation. If the plaintext is viewed as a sequence of bits, then substitution method comes into picture which involves replacing plaintext bit patterns with cipher text bit patterns. View homework help 02classical from math 201 at punjab college multan.
Lawrie browns slides supplied with william stallings s book cryptography and network security. Ahmed elshafee, acu spring 2014, information security. Lecture slides by lawrie brown for cryptography and network security, 5e, by william stallings, chapter 2 classical encryption techniques. The strategy used by the cryptanalysis depends on the nature of the encryption scheme and the. Apr 18, 2020 classical encryption techniques, there are two basic building blocks of all encryption techniques.