Found 359 Articles for Information Security

There are various elements of DES which are as follows −Use of S-Boxes − The tables used for substitution i.e., the S-boxes, in DES are kept hidden by IBM. IBM supports that it took them over 17 person years to appear up with the internal design of the S-boxes.Key Length − Cryptographic system has two important elements including the cryptographic algorithm and the key. The inner operating of the DES algorithm are completely popular to the general public. Hence, the strength of the DES lies only in the other element including its key, which should be secret.Differential Cryptanalysis − Differential ... Read More

This operation expands the right half of the information, R from 32 bits to 48 bits and this operation changes the order of the bits as well as repeating specific bits. It is called an expansion permutation.This operation has two objective including it creates the right half the similar size as the key for the XOR operation and it supports a longer result that can be compressed during the substitution operation. It can be enabling one bit influence two substitutions, the dependency of the output bits on the input bits spread quicker. This is known as avalanche effect.DES is designed ... Read More

DES uses 16 rounds. Each of the 16 rounds includes the broad-level steps are as follows −Key Transformation − An initial 64-bit key is changed into a 56-bit key by discarding each 8th bit of the initial key. Therefore for each round, a 56 bit key is available. From this 56-bit key, a different 48-bit subkey is generated during each round using a process is known as key transformation.The 56-bit key is divided into two halves, each of 28 bits. These halves are circularly shifted left by one or two positions, based on the round.For instance, if the round number ... Read More

A cryptographic hash function is a transformation that creates an input (or message) and restore a fixed-size string, which is known as the hash value. A hash value h is produced by a function H of the form −h = H(M)where M is the variable length message and H (M) is the fixed length hash value.Hash functions are generally used mathematical functions in cryptography for executing security. A hash function transform an input value of any arbitrary size to a fixed-size value. Therefore, the input can be of any length but the output produced is always of a fixed length. ... Read More

An initial permutation is required only once at the starting of the encryption process. In DES, after the complete plaintext is divided into blocks of 64 bits each, IP is required on each of them. This initial permutation is a phase in the transposition procedure.The initial permutation appears only once, and it appears before the first round. It recommend how the transposition in IP should proceed, as display in the table.For example, it can said that the IP restore the first bit of the original plain-text block with the 58th bit of the original plaintext block, and the second bit ... Read More

DES is a block cipher. The encryption procedure is create of two permutations (Pboxes) that can be defined initial and final permutations, and 16 Feistel rounds. Each round need a different 48-bit round key produced from the cipher key in accordance with a predefined algorithm.DES is based on the two essential attributes of cryptography including substitution (also known as confusion) and transposition (also known as diffusion). DES includes 16 steps, each of which is known as round.Each round implements the steps of substitution and transposition. DES is a symmetric cryptosystem. A block is be enciphered is inflicted to an initial ... Read More

A cryptographic hash function is a numerical function used in cryptography. A cryptographic hash function integrate the message-passing capabilities of hash functions with security features.The term hash function has been used in computer science from quite frequently and it define as a function that compresses a string of arbitrary input to a string of settled length. However if it satisfies some more requirements, thus it can be used for cryptographic applications and then it is called a Cryptographic Hash functions.Cryptographic Hash functions are the most essential tool in the field of cryptography and are used to manage a number of ... Read More

There are several applications of cryptographic hash function are as follows −Digital Signature − Hand-written signature is a method to prove that a paper file is signed by us and not by someone else. It can prove this and the current hand-written signature is compared with one or more of the earlier handwritten signatures.If there is a match then the recipient of the files can securely accept that the files could not have been endorsed by someone else. In case it is the first time, it can have to prove the identity by means of some recognition card, and necessarily ... Read More

Data Encryption Standard (DES) is a block cipher algorithm that creates plain text in blocks of 64 bits and transform them to ciphertext using keys of 48 bits. It is a symmetric key algorithm, which defines that the similar key is used for encrypting and decrypting information.DES takes a 64-bit plaintext and produce a 64-bit ciphertext; at the decryption site, DES takes a 64-bit ciphertext and produce a 64-bit block of plaintext. The same 56-bit cipher key can be used for both encryption and decryption.The key nature of DES is that the algorithms is fixed and is public data. However, ... Read More

There are various attacks on DES which are as follows −Differential Cryptanalysis − The main objective of differential cryptanalysis is to view for statistical distributions and patterns in ciphertext to provide deduce element about the key used in the cipher.Differential cryptanalysis is a section of study in cryptography that compares the method differences in input associated to the differences in encrypted output. It can be used basically in the study of block ciphers to decide if changes in plaintext result in any non-random outcomes in the encrypted ciphertext.Related-Key Cryptanalysis − Related-key cryptanalysis consider that the attacker understand the encryption of ... Read More