Feistel block cipher is a structure used to derive many symmetric block ciphers such as DES which we have discussed in our previous content. Feistel cipher proposed a structure which implements substitution and permutation alternately to obtain cipher text from the pain text and vice-versa. In the Feistel block cipher, each block has to undergo many rounds where each round … [Read more...] about Feistel Block Cipher
Block Cipher
Block cipher is an encryption and decryption method which operates on the blocks of plain text, instead of operating on each bit of plain text separately. Each block is of equal size and has fixed no of bits. The generated ciphertext has blocks equal to the number of blocks in plaintext and also has the same number of bits in each block as of plain text. Block cipher uses the … [Read more...] about Block Cipher
Data Encryption Standard (DES)
Data Encryption Standard (DES) is the symmetric block cipher which encrypts a 64-bit plain text in a 64-bit ciphertext. The DES was introduced by the National Institute of Standard and Technology (NIST) in the 1970s. Initially, DES was only used in financial applications but later it was accepted as the cryptographic algorithm by other organizations too. Being a symmetric … [Read more...] about Data Encryption Standard (DES)
Transposition Technique in Cryptography
Transposition technique is an encryption method which is achieved by performing permutation over the plain text. Mapping plain text into cipher text using transposition technique is called transposition cipher. In this section, we will discuss variations of transposition technique, and we will also observe how the transposition technique is different from the substitution … [Read more...] about Transposition Technique in Cryptography
Substitution Technique in Cryptography
Substitution technique is a classical encryption technique where the characters present in the original message are replaced by the other characters or numbers or by symbols. If the plain text (original message) is considered as the string of bits, then the substitution technique would replace bit pattern of plain text with the bit pattern of cipher text. We will discuss … [Read more...] about Substitution Technique in Cryptography
Difference Between Black Box Testing and White Box Testing
Black box testing and white box testing both are the methods of testing the software. But, the main difference between black box and white box is that the black box testing checks the functionality of the software (external view) whereas, the white box testing, tests the internal structure or procedural design (internal view) of the software. Black box testing and white box … [Read more...] about Difference Between Black Box Testing and White Box Testing
Basis Path Testing
Basis path testing derives the number of 'test cases' that can be designed to exercise each & every statement in the program at the minimum once while testing is conducted to uncover all the possible errors of the program. Basis path testing is a method of testing the control structure of conventional software. In this section, we will discuss the steps for conducting … [Read more...] about Basis Path Testing
Black-Box Testing
Black-box testing is a ‘software testing technique’ used to examine the functionality of the software instead of bothering about the ‘internal structure’ of the software. It is also termed as behavioral testing as it examines the behavior of the software. Black box testing analyzes different categories of errors by testing all the functions of the software. In this section, … [Read more...] about Black-Box Testing
Software Testing Strategies
Software testing strategy is an approach which incorporates planning of the steps to test the software along with the planning of time, effort & resources that will be required to test the software. Software testing strategies plans to test any software starting from the smallest component of the software and then integrating test towards the complete system. The testing … [Read more...] about Software Testing Strategies
Software Quality Assurance (SQA)
Software quality assurance is a set of activities followed by software engineers to ensures that the software meets the specified requirements of the user, and it does not have any error. Along with this the software is able to manage risk and secures the data of user at each level. Though maintaining the quality of the software is looked after by the software developing … [Read more...] about Software Quality Assurance (SQA)