Safe & Security Articles - Page 49 of 93

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

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

The Secure Hash Algorithm (SHA) was invented by the National Security Agency (NSA) and published in 1993 through the National Institute of Standard and Technology (NIST) as a U.S. Federal Information Processing Standard (FIPS PUB 180).SHA depends on and shares the similar building blocks as the MD4 algorithm. The design of SHA introduced a new process which develop the 16-word message block input to the compression function to an 80-word block between other things.The processing of SHA works as follows −Step 1 − Append padding bits − The original message is padded and its duration is congruent to 448 modulo ... Read More

DES is a strong encryption standard that works on a 64-bits plaintext block and restore a 64-bits ciphertext. Therefore, DES results in a permutation between the 264 possible arrangements of 64 bits, each of which can be either 0 or 1.DES has 16 rounds and it can use the same set of techniques on the plaintext block 16 times. Any round less can create DES vulnerable to differential cryptanalysis.In Data Encryption Standard, the 64 bit plaintext block is subjected to an initial permutation which does not based on the key, whereas the inverse of this permutation completed off the algorithm and ... Read More

SHA stands for secure hashing algorithm. SHA is a modified version of MD5 and used for hashing information and certificates. A hashing algorithm shortens the input information into a smaller form that cannot be learned by utilizing bitwise operations, modular additions, and compression functions.SHAs also help in revealing if an original message was transformed in any way. By imputing the original hash digest, a user can tell if even an individual letter has been shifted, as the hash digests will be effectively different.The important element of SHAs are that they are deterministic. This define that consider the hash function used ... Read More

DES stands for Data Encryption Standard. The Data Encryption Standards (DES) algorithm was invented by IBM in the early 1970s. It obtain the plaintext in 64-bit blocks and changes it into the ciphertext that need the 64-bit keys to encrypt the information. The algorithm need the similar key to encrypt and decrypt the information.DES is a symmetric key algorithm used to encrypt digital data. Its short key length of 56 bits renders DES too insecure to secure most current applications that is based on encryption.DES uses block cipher technology to change fixed-length bitstrings into same-sized, encrypted bitstrings. While the standard ... Read More