In the symmetric cryptography a single key is used for encrypting and decryption the data. 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. 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 the limitation of this encryption technique that this private key must be distributed only among the authorized sender and receiver. Classical techniques symmetric model substitution transposition rotor machines steganography characterising cryptographic systems operations used for encryption.
Sep 16, 20 classical encryption techniques in network security 1. 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 my implementation for some classical encryption techniques. Apr 18, 2020 classical encryption techniques, there are two basic building blocks of all encryption techniques. If we look at the figure below we can better understand. 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. Classical encryption techniques in cryptography and network. 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. Ahmed elshafee, acu spring 2014, information security. This approach is also called as posteriori approach.
Analytical study on encryption techniques and challenges in. This allows the sharing of electronic information and resources. In case m 3, the encryption can be expressed in terms of the matrix multiplication as follows. Almost all secret key ciphers are essentially a combination of two simple techniques. Starting with the origins of cryptography, it moves on to explain cryptosystems, various traditional and modern ciphers.
Integrating classical encryption with modern technique. 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. The many schemes available today for encryption and decryption. Lawrie browns slides supplied with william stallings s book cryptography and network security. Substitution the letters of plaintext are replaced by other letters or by numbers or symbols. Given the algorithm and ciphertext, an attacker cannot obtain the key or plaintext. These chips are widely available and incorporated into a number of products. Starting with algebraic equations, this paper touches on how finite fields work and how they can be used in everyday life. Classical encryption techniques as opposed to modern cryptography symmetrickey.
Introduction to finite fields and their applications pdf. It explains how programmers and network professionals can use cryptography to maintain the privacy of computer data. With the use of symmetric encryption, the principal security problem is maintaining the secrecy of the key. Classical encryption techniques free download as powerpoint presentation. 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. 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. Substitutionreplace one element in plaintext with another transpositionrearrange elements product systemsmultiple stages of substitutions and transpositions number of keys used. Lecture slides by lawrie brown for cryptography and network security, 5e, by william stallings, chapter 2 classical encryption techniques. Classical encryption techniques jordan university of. Classical encryption techniques symmetric cipher model.
Building blocks of classical encryption techniques. Basic vocabulary of encryption and decryption plaintext. Cryptanalysis the process of attempting to discover x or k or both is known as cryptanalysis. The internet is a worldwide network of connected computers. Classical techniques are based on two building blocks. Loai tawalbeh computer engineering department jordan university of science and technology jordan cpe 542.
Some basic vocabulary of computer and network security and a. Mar 01, 20 plaintext encrypted two letters at a time. Classical encryption techniques cryptography cipher. Encryption is a security method in which information is encoded in such a way that only authorized user can read it.
The encryption algorithm performs various substitutions and transformations on the plaintext. Replace characters of plaintext by other characters. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Classical encryption techniques in cryptography and network security. This is essentially the encryption algorithm run in reverse. 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.
The secret key is also input to the encryption algorithm. Comparing classical encryption with modern 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 encryption1. Substitution means replacing an element of the plaintext with an element of cipher text. It remains by far the most widely used of the two types of encryption. Discovering the algorithm that performs better for large as well as for small instances is critical. Cryptanalysis of monoalphabetic the relative frequencies of the letters in the. These two keys are mathematically linked with each other. Classical and modern encryption techniques are investigated and then compared here. Symmetric key encryption algorithm uses same cryptographic keys for both. A general paradigm for algorithm design threestep process. It takes the ciphertext and the secret key and produces the original plaintext.
Uses information such as plaintextciphertext pairs to deduce the key. The many schemes used for encryption constitute the area of study known as cryptography. Pdf comparing classical encryption with modern techniques. Classical encryption techniques developed lowcost chip implementations of data encryption algorithms. Loai tawalbeh fall 2005 basic terminology plaintext the original message ciphertext the coded message. Chapter 2 classical encryption techniques flashcards. If a pair is a repeated letter, insert a filler like x, ex. Transposition means rearranging the order of appearance of the elements of the plaintext. Request pdf analysis of classical encryption techniques in cloud computing cloud computing has become a significant computing model in the it industry. Fully homomorphic encryption without modulus switching. There are two types of encryptions schemes as listed below. The national security agency nsa is responsible for higher levels of security. Classical cryptography and quantum cryptography geeksforgeeks. Classical encryption techniques raj jain washington university in saint louis saint louis, mo 63.
Classical encryption techniques computer science and. It uses encryption algorithm to generate ciphertext that can only be read if decrypted. Classical encryption techniques in cryptography and network security free download as powerpoint presentation. Bruteforce attack try every key to decipher the ciphertext.
View homework help 02classical from math 201 at punjab college multan. Analytical study on encryption techniques and challenges. A symmetric encryption scheme has five ingredients. A substitution technique is one in which the words or text of plaintext are replaced by other letters or by numbers or symbols. 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.
Classical encryption techniques linkedin slideshare. Network security classical encryption techniques 2. The strategy used by the cryptanalysis depends on the nature of the encryption scheme and the. Public key encryption algorithm uses pair of keys, one of which is a secret key and one of which is public. Classical encryption techniques in cryptography and. This tutorial covers the basics of the science of cryptography. This is the original intelligible message or data that is fed into the algorithm as input. 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.
Analysis of classical encryption techniques in cloud. Two building blocks of all classical encryption techniques are substitution and transposition. 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. The encryption takes m successive plaintext letter and substitutes them for m ciphertext letters.
Classical encryption techniques in network security 1. 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. Thisgeneralideaisillustrated in figure 1 for the case of n 4. Techniques used for deciphering a message without any knowledge of the enciphering details fall into the area of cryptanalysis. It is the hash function that generates the hash code, which helps. The process of protecting information by transforming encrypting it into an unreadable format is called cryptography. Start studying chapter 2 classical encryption techniques. In general, though, n is set to 64 or multiples thereof.
Nov 07, 2016 lecture slides by lawrie brown for cryptography and network security, 5e, by william stallings, chapter 2 classical encryption techniques. Classical encryption techniques there are two requirements for secure use of conventional encryption. Sender and receiver must have obtained copies of the secret key in a secure fashion and must keep the key secure. Classical encryption techniques lecture notes on computer and network security. Classical encryption techniques in network security. With the message x and the encryption key k as input, the encryption algorithm forms the ciphertext y y1, y2. Secret key ciphers use a secret key for encryption. In terms of security, hashing is a technique used to encrypt data and generate unpredictable hash values. Of the plaintext is viewed as a sequence of bits, then substitution involves replacing plaintext bit patterns with ciphertext bit patterns 2. Classical cryptography has two types of techniques.
Such a scheme is known as a cryptographic system cryptosystem or a cipher. Only those who possess secret key can decipher decrypt the message into plain text. 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. Chosen plaintext attacker selects plaintext and gets ciphertext chosen international it university is 09 spring 2017 lecture 2. 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. Cryptography and network security for computers and email.