DATA ENCRYPTION STANDARD(DES)

Task 1: Writing a report describing how the Data Encryption Standard

(DES) works.

Data Encryption Standard

Introduction

The Data Encryption Standard (DES) is a block cipher (a form of shared secret encryption) that was selected by the National Bureau of Standards as an official Federal Information Processing Standard (FIPS) for the United States in 1976 and which has subsequently enjoyed widespread use internationally. It is based on a symmetric-key algorithm that uses a 56-bit key. The algorithm was initially controversial with classified design elements, a relatively short key length, and suspicions about a National Security Agency (NSA) backdoor. DES consequently came under intense academic scrutiny which motivated the modern understanding of block ciphers and their cryptanalysis.

How a Plaintext is Encrypted and then Decrypted?

This walkthrough shows you how to use the DESCryptoServiceProvider class to encrypt and decrypt strings using the cryptographic service provider (CSP) version of the Triple Data Encryption Standard (TripleDES) algorithm. The first step is to create a simple wrapper class that encapsulates the 3DES algorithm and stores the encrypted data as a base-64 encoded string. Then, that wrapper is used to securely store private user data in a publicly accessible text file.

You can use encryption to protect user secrets (for example, passwords) and to make credentials unreadable by unauthorized users. This can protect an authorized user's identity from being stolen, which protects the user's assets and provides non-repudiation. Encryption can also protect a user's data from being accessed by unauthorized users.

How DES works explaining the encryption procedures.

In 1972, the National Institute of Standards and Technology (called the National Bureau of Standards at the time) decided that a strong cryptographic algorithm was needed to protect non-classified information. The algorithm was required to be cheap, widely available, and very secure. NIST envisioned something that would be available to the general public and could be used in a wide variety of applications. So they asked for public proposals for such an algorithm. In 1974 IBM submitted the Lucifer algorithm, which appeared to meet most of NIST's design requirements.

NIST enlisted the help of the National Security Agency to evaluate the security of Lucifer. At the time many people distrusted the NSA due to their extremely secretive activities, so there was initially a certain degree of skepticism regarding the analysis of Lucifer. One of the greatest worries was that the key length, originally 128 bits, was reduced to just 56 bits, weakening it significantly. The NSA was also accused of changing the algorithm to plant a "back door" in it that would allow agents to decrypt any information without having to know the encryption key. But these fears proved unjustified and no such back door has ever been found. The modified Lucifer algorithm was adopted by NIST as a federal standard on November 23, 1976. Its name was changed to the Data Encryption Standard (DES). The algorithm specification was published in January 1977, and with the official backing of the government it became a very widely employed algorithm in a short amount of ...