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The KCV is the 'Key Check Value' for the key, calculated by assuming the key/components are 3DES keys, and encrypting a string of binary zeroes. The KCV is the first six hex digits of the resulting ciphertext. Gets or sets the secret key for the TripleDES algorithm.

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Triple Des Encryption Code In C#

The Data Encryption Standard (DES) is a symmetric-key block cipher published by the National Institute of Standards and Technology (NIST).

DES is an implementation of a Feistel Cipher. It uses 16 round Feistel structure. The block size is 64-bit. Though, key length is 64-bit, DES has an effective key length of 56 bits, since 8 of the 64 bits of the key are not used by the encryption algorithm (function as check bits only). General Structure of DES is depicted in the following illustration −

The Data Encryption Standard encryption algorithm on which Triple DES is based was first published in 1975. Over the years, as computers grew faster, the block cipher with a simple 56-bit key. Apr 07, 2015  how to implement triple DES Encryption in C# Urdu / Hindi Tutorial. Data Encryption Standard (DES): Key Schedule and Decryption by Christof Paar. 3D Map Generator Terrain - Duration. Aug 17, 2018  Data encryption standard (DES) has been found vulnerable against very powerful attacks and therefore, the popularity of DES has been found slightly on decline. DES is a block cipher, and encrypts data in blocks of size of 64 bit each, means 64 bits of plain text goes as the input to DES, which produces 64 bits of cipher text.

Since DES is based on the Feistel Cipher, all that is required to specify DES is −

• Round function
• Key schedule
• Any additional processing − Initial and final permutation

Jul 09, 2015  I need to generate byte array for TripleDES encryption. I don't want to use.generateKey because I need to know the bytes in the key to pass them to another application. Thanks for the replies but I forgot to mention one thing: the bytes have to be odd parity. Apr 11, 2014  DES is a broken cypher and this work is intended for educational purpose. DES.c and DES.h contain the functions used in the DES algorithm. Main.c builds the algorithm and allows you to encrypt/decrypt an input file. Use make to build desbox. $ make $ desbox -help genkey.c is a key generator that prevents weak keys. Use it if you don't.

Initial and Final Permutation

The initial and final permutations are straight Permutation boxes (P-boxes) that are inverses of each other. They have no cryptography significance in DES. The initial and final permutations are shown as follows −

Round Function

The heart of this cipher is the DES function, f. The DES function applies a 48-bit key to the rightmost 32 bits to produce a 32-bit output.

• Expansion Permutation Box − Since right input is 32-bit and round key is a 48-bit, we first need to expand right input to 48 bits. Permutation logic is graphically depicted in the following illustration −

• The graphically depicted permutation logic is generally described as table in DES specification illustrated as shown −

• XOR (Whitener). − After the expansion permutation, DES does XOR operation on the expanded right section and the round key. The round key is used only in this operation.

• Substitution Boxes. − The S-boxes carry out the real mixing (confusion). DES uses 8 S-boxes, each with a 6-bit input and a 4-bit output. Refer the following illustration −

• The S-box rule is illustrated below −

• There are a total of eight S-box tables. The output of all eight s-boxes is then combined in to 32 bit section.

• Straight Permutation − The 32 bit output of S-boxes is then subjected to the straight permutation with rule shown in the following illustration:

Key Generation

The round-key generator creates sixteen 48-bit keys out of a 56-bit cipher key. The process of key generation is depicted in the following illustration −

The logic for Parity drop, shifting, and Compression P-box is given in the DES description.

DES Analysis

Triple Des Key Generator Club

The DES satisfies both the desired properties of block cipher. These two properties make cipher very strong.

• Avalanche effect − A small change in plaintext results in the very great change in the ciphertext.

• Completeness − Each bit of ciphertext depends on many bits of plaintext.

During the last few years, cryptanalysis have found some weaknesses in DES when key selected are weak keys. These keys shall be avoided.

DES has proved to be a very well designed block cipher. There have been no significant cryptanalytic attacks on DES other than exhaustive key search.