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### Weka

This is a code for Data Encryption Standard Algorithm(DES) using C programming language
cpp code
`/******************************************************************************                                                                            **  --------------------------------- des.c --------------------------------  **                                                                            ******************************************************************************/#include <math.h>#include <stdlib.h>#include <string.h>#include "bit.h"#include "encrypt.h"/******************************************************************************                                                                            **  Define a mapping for the key transformation.                              **                                                                            ******************************************************************************/static const int DesTransform[56] = {   57, 49, 41, 33, 25, 17,  9,  1, 58, 50, 42, 34, 26, 18,   10,  2, 59, 51, 43, 35, 27, 19, 11,  3, 60, 52, 44, 36,   63, 55, 47, 39, 31, 23, 15,  7, 62, 54, 46, 38, 30, 22,   14,  6, 61, 53, 45, 37, 29, 21, 13,  5, 28, 20, 12,  4};/******************************************************************************                                                                            **  Define the number of rotations for computing subkeys.                     **                                                                            ******************************************************************************/static const int DesRotations[16] = {   1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};/******************************************************************************                                                                            **  Define a mapping for the permuted choice for subkeys.                     **                                                                            ******************************************************************************/static const int DesPermuted[48] = {   14, 17, 11, 24,  1,  5,  3, 28, 15,  6, 21, 10,   23, 19, 12,  4, 26,  8, 16,  7, 27, 20, 13,  2,   41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,   44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32};/******************************************************************************                                                                            **  Define a mapping for the initial permutation of data blocks.              **                                                                            ******************************************************************************/static const int DesInitial[64] = {   58, 50, 42, 34, 26, 18, 10,  2, 60, 52, 44, 36, 28, 20, 12,  4,   62, 54, 46, 38, 30, 22, 14,  6, 64, 56, 48, 40, 32, 24, 16,  8,   57, 49, 41, 33, 25, 17,  9,  1, 59, 51, 43, 35, 27, 19, 11,  3,   61, 53, 45, 37, 29, 21, 13,  5, 63, 55, 47, 39, 31, 23, 15,  7};/******************************************************************************                                                                            **  Define a mapping for the expansion permutation of data blocks.            **                                                                            ******************************************************************************/static const int DesExpansion[48] = {   32,  1,  2,  3,  4,  5,  4,  5,  6,  7,  8,  9,    8,  9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17,   16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25,   24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32,  1};/******************************************************************************                                                                            **  Define tables for the S-box substitutions performed for data blocks.      **                                                                            ******************************************************************************/static const int DesSbox[8][4][16] = {   {   {14,  4, 13,  1,  2, 15, 11,  8,  3, 10,  6, 12,  5,  9,  0,  7},   { 0, 15,  7,  4, 14,  2, 13,  1, 10,  6, 12, 11,  9,  5,  3,  8},   { 4,  1, 14,  8, 13,  6,  2, 11, 15, 12,  9,  7,  3, 10,  5,  0},   {15, 12,  8,  2,  4,  9,  1,  7,  5, 11,  3, 14, 10,  0,  6, 13},   },   {   {15,  1,  8, 14,  6, 11,  3,  4,  9,  7,  2, 13, 12,  0,  5, 10},   { 3, 13,  4,  7, 15,  2,  8, 14, 12,  0,  1, 10,  6,  9, 11,  5},   { 0, 14,  7, 11, 10,  4, 13,  1,  5,  8, 12,  6,  9,  3,  2, 15},   {13,  8, 10,  1,  3, 15,  4,  2, 11,  6,  7, 12,  0,  5, 14,  9},   },   {   {10,  0,  9, 14,  6,  3, 15,  5,  1, 13, 12,  7, 11,  4,  2,  8},   {13,  7,  0,  9,  3,  4,  6, 10,  2,  8,  5, 14, 12, 11, 15,  1},   {13,  6,  4,  9,  8, 15,  3,  0, 11,  1,  2, 12,  5, 10, 14,  7},   { 1, 10, 13,  0,  6,  9,  8,  7,  4, 15, 14,  3, 11,  5,  2, 12},   },   {   { 7, 13, 14,  3,  0,  6,  9, 10,  1,  2,  8,  5, 11, 12,  4, 15},   {13,  8, 11,  5,  6, 15,  0,  3,  4,  7,  2, 12,  1, 10, 14,  9},   {10,  6,  9,  0, 12, 11,  7, 13, 15,  1,  3, 14,  5,  2,  8,  4},   { 3, 15,  0,  6, 10,  1, 13,  8,  9,  4,  5, 11, 12,  7,  2, 14},   },   {   { 2, 12,  4,  1,  7, 10, 11,  6,  8,  5,  3, 15, 13,  0, 14,  9},   {14, 11,  2, 12,  4,  7, 13,  1,  5,  0, 15, 10,  3,  9,  8,  6},   { 4,  2,  1, 11, 10, 13,  7,  8, 15,  9, 12,  5,  6,  3,  0, 14},   {11,  8, 12,  7,  1, 14,  2, 13,  6, 15,  0,  9, 10,  4,  5,  3},   },   {   {12,  1, 10, 15,  9,  2,  6,  8,  0, 13,  3,  4, 14,  7,  5, 11},   {10, 15,  4,  2,  7, 12,  9,  5,  6,  1, 13, 14,  0, 11,  3,  8},   { 9, 14, 15,  5,  2,  8, 12,  3,  7,  0,  4, 10,  1, 13, 11,  6},   { 4,  3,  2, 12,  9,  5, 15, 10, 11, 14,  1,  7,  6,  0,  8, 13},   },   {   { 4, 11,  2, 14, 15,  0,  8, 13,  3, 12,  9,  7,  5, 10,  6,  1},   {13,  0, 11,  7,  4,  9,  1, 10, 14,  3,  5, 12,  2, 15,  8,  6},   { 1,  4, 11, 13, 12,  3,  7, 14, 10, 15,  6,  8,  0,  5,  9,  2},   { 6, 11, 13,  8,  1,  4, 10,  7,  9,  5,  0, 15, 14,  2,  3, 12},   },   {   {13,  2,  8,  4,  6, 15, 11,  1, 10,  9,  3, 14,  5,  0, 12,  7},   { 1, 15, 13,  8, 10,  3,  7,  4, 12,  5,  6, 11,  0, 14,  9,  2},   { 7, 11,  4,  1,  9, 12, 14,  2,  0,  6, 10, 13, 15,  3,  5,  8},   { 2,  1, 14,  7,  4, 10,  8, 13, 15, 12,  9,  0,  3,  5,  6, 11},   },};/******************************************************************************                                                                            **  Define a mapping for the P-box permutation of data blocks.                **                                                                            ******************************************************************************/static const int DesPbox[32] = {   16,  7, 20, 21, 29, 12, 28, 17,  1, 15, 23, 26,  5, 18, 31, 10,    2,  8, 24, 14, 32, 27,  3,  9, 19, 13, 30,  6, 22, 11,  4, 25};/******************************************************************************                                                                            **  Define a mapping for the final permutation of data blocks.                **                                                                            ******************************************************************************/static const int DesFinal[64] = {   40,  8, 48, 16, 56, 24, 64, 32, 39,  7, 47, 15, 55, 23, 63, 31,   38,  6, 46, 14, 54, 22, 62, 30, 37,  5, 45, 13, 53, 21, 61, 29,   36,  4, 44, 12, 52, 20, 60, 28, 35,  3, 43, 11, 51, 19, 59, 27,   34,  2, 42, 10, 50, 18, 58, 26, 33,  1, 41,  9, 49, 17, 57, 25};/******************************************************************************                                                                            **  Define a type for whether to encipher or decipher data.                   **                                                                            ******************************************************************************/typedef enum DesEorD_ {encipher, decipher} DesEorD;/******************************************************************************                                                                            **  -------------------------------- permute -------------------------------  **                                                                            ******************************************************************************/static void permute(unsigned char *bits, const int *mapping, int n) {unsigned char      temp[8];int                i;/******************************************************************************                                                                            **  Permute the buffer using an n-entry mapping.                              **                                                                            ******************************************************************************/memset(temp, 0, (int)ceil(n / );for (i = 0; i < n; i++)   bit_set(temp, i, bit_get(bits, mapping[i] - 1));memcpy(bits, temp, (int)ceil(n / );return;}/******************************************************************************                                                                            **  ------------------------------- des_main -------------------------------  **                                                                            ******************************************************************************/static int des_main(const unsigned char *source, unsigned char *target, const   unsigned char *key, DesEorD direction) {static unsigned char subkeys[16][7];unsigned char        temp[8],                     lkey[4],                     rkey[4],                     lblk[6],                     rblk[6],                     fblk[6],                     xblk[6],                     sblk;int                  row,                     col,                     i,                     j,                     k,                     p;/******************************************************************************                                                                            **  If key is NULL, use the subkeys as computed in a previous call.           **                                                                            ******************************************************************************/if (key != NULL) {   /**************************************************************************   *                                                                         *   *  Make a local copy of the key.                                          *   *                                                                         *   **************************************************************************/   memcpy(temp, key, ;   /**************************************************************************   *                                                                         *   *  Permute and compress the key into 56 bits.                             *   *                                                                         *   **************************************************************************/   permute(temp, DesTransform, 56);   /**************************************************************************   *                                                                         *   *  Split the key into two 28-bit blocks.                                  *   *                                                                         *   **************************************************************************/   memset(lkey, 0, 4);   memset(rkey, 0, 4);   for (j = 0; j < 28; j++)      bit_set(lkey, j, bit_get(temp, j));   for (j = 0; j < 28; j++)      bit_set(rkey, j, bit_get(temp, j + 28));   /**************************************************************************   *                                                                         *   *  Compute the subkeys for each round.                                    *   *                                                                         *   **************************************************************************/   for (i = 0; i < 16; i++) {      /***********************************************************************      *                                                                      *      *  Rotate each block according to its round.                           *      *                                                                      *      ***********************************************************************/      bit_rot_left(lkey, 28, DesRotations[i]);      bit_rot_left(rkey, 28, DesRotations[i]);      /***********************************************************************      *                                                                      *      *  Concatenate the blocks into a single subkey.                        *      *                                                                      *      ***********************************************************************/      for (j = 0; j < 28; j++)         bit_set(subkeys[i], j, bit_get(lkey, j));      for (j = 0; j < 28; j++)         bit_set(subkeys[i], j + 28, bit_get(rkey, j));      /***********************************************************************      *                                                                      *      *  Do the permuted choice permutation.                                 *      *                                                                      *      ***********************************************************************/      permute(subkeys[i], DesPermuted, 48);   }}/******************************************************************************                                                                            **  Make a local copy of the source text.                                     **                                                                            ******************************************************************************/memcpy(temp, source, ;/******************************************************************************                                                                            **  Do the initial permutation.                                               **                                                                            ******************************************************************************/permute(temp, DesInitial, 64);/******************************************************************************                                                                            **  Split the source text into a left and right block of 32 bits.             **                                                                            ******************************************************************************/memcpy(lblk, &temp[0], 4);memcpy(rblk, &temp[4], 4);/******************************************************************************                                                                            **  Encipher or decipher the source text.                                     **                                                                            ******************************************************************************/for (i = 0; i < 16; i++) {   /**************************************************************************   *                                                                         *   *  Begin the computation of f.                                            *   *                                                                         *   **************************************************************************/   memcpy(fblk, rblk, 4);   /**************************************************************************   *                                                                         *   *  Permute and expand the copy of the right block into 48 bits.           *   *                                                                         *   **************************************************************************/   permute(fblk, DesExpansion, 48);   /**************************************************************************   *                                                                         *   *  Apply the appropriate subkey for the round.                            *   *                                                                         *   **************************************************************************/   if (direction == encipher) {      /***********************************************************************      *                                                                      *      *  For enciphering, subkeys are applied in increasing order.           *      *                                                                      *      ***********************************************************************/      bit_xor(fblk, subkeys[i], xblk, 48);      memcpy(fblk, xblk, 6);      }   else {      /***********************************************************************      *                                                                      *      *  For deciphering, subkeys are applied in decreasing order.           *      *                                                                      *      ***********************************************************************/      bit_xor(fblk, subkeys[15 - i], xblk, 48);      memcpy(fblk, xblk, 6);   }   /**************************************************************************   *                                                                         *   *  Do the S-box substitutions.                                            *   *                                                                         *   **************************************************************************/   p = 0;   for (j = 0; j < 8; j++) {      /***********************************************************************      *                                                                      *      *  Compute a row and column into the S-box tables.                     *      *                                                                      *      ***********************************************************************/      row = (bit_get(fblk, (j * 6)+0) * 2) + (bit_get(fblk, (j * 6)+5) * 1);      col = (bit_get(fblk, (j * 6)+1) *  + (bit_get(fblk, (j * 6)+2) * 4) +            (bit_get(fblk, (j * 6)+3) * 2) + (bit_get(fblk, (j * 6)+4) * 1);      /***********************************************************************      *                                                                      *      *  Do the S-box substitution for the current six-bit block.            *      *                                                                      *      ***********************************************************************/      sblk = (unsigned char)DesSbox[j][row][col];      for (k = 4; k < 8; k++) {         bit_set(fblk, p, bit_get(&sblk, k));         p++;      }   }   /**************************************************************************   *                                                                         *   *  Do the P-box permutation to complete f.                                *   *                                                                         *   **************************************************************************/   permute(fblk, DesPbox, 32);   /**************************************************************************   *                                                                         *   *  Compute the XOR of the left block and f.                               *   *                                                                         *   **************************************************************************/   bit_xor(lblk, fblk, xblk, 32);   /**************************************************************************   *                                                                         *   *  Set the left block for the round.                                      *   *                                                                         *   **************************************************************************/   memcpy(lblk, rblk, 4);   /**************************************************************************   *                                                                         *   *  Set the right block for the round.                                     *   *                                                                         *   **************************************************************************/   memcpy(rblk, xblk, 4);}/******************************************************************************                                                                            **  Set the target text to the rejoined final right and left blocks.          **                                                                            ******************************************************************************/memcpy(&target[0], rblk, 4);memcpy(&target[4], lblk, 4);/******************************************************************************                                                                            **  Do the final permutation.                                                 **                                                                            ******************************************************************************/permute(target, DesFinal, 64);return 0;}/******************************************************************************                                                                            **  ----------------------------- des_encipher -----------------------------  **                                                                            ******************************************************************************/void des_encipher(const unsigned char *plaintext, unsigned char *ciphertext,   const unsigned char *key) {des_main(plaintext, ciphertext, key, encipher);return;}/******************************************************************************                                                                            **  ----------------------------- des_decipher -----------------------------  **                                                                            ******************************************************************************/void des_decipher(const unsigned char *ciphertext, unsigned char *plaintext,   const unsigned char *key) {des_main(ciphertext, plaintext, key, decipher);return;}`

Used Codes in this algorithm :
c-code-examples/bit-operations-set-get-xor-rotate-on-bits-arrays-t10771.html
src book
Code:
"Mastering Algorithms with C"  by Kyle Loudon

Encrypt.h
cpp code
`/******************************************************************************                                                                            **  ------------------------------- encrypt.h ------------------------------  **                                                                            ******************************************************************************/#ifndef ENCRYPT_H#define ENCRYPT_H/******************************************************************************                                                                            **  In a secure implementation, Huge should be at least 400 decimal digits,   **  instead of the 10 below (ULONG_MAX = 4294967295).                         **                                                                            ******************************************************************************/typedef unsigned long Huge;/******************************************************************************                                                                            **  Define a structure for RSA public keys.                                   **                                                                            ******************************************************************************/typedef struct RsaPubKey_ {Huge               e;Huge               n;} RsaPubKey;/******************************************************************************                                                                            **  Define a structure for RSA private keys.                                  **                                                                            ******************************************************************************/typedef struct RsaPriKey_ {Huge               d;Huge               n;} RsaPriKey;/******************************************************************************                                                                            **  --------------------------- Public Interface ---------------------------  **                                                                            ******************************************************************************/void des_encipher(const unsigned char *plaintext, unsigned char *ciphertext,   const unsigned char *key);void des_decipher(const unsigned char *ciphertext, unsigned char *plaintext,   const unsigned char *key);void rsa_encipher(Huge plaintext, Huge *ciphertext, RsaPubKey pubkey);void rsa_decipher(Huge ciphertext, Huge *plaintext, RsaPriKey prikey);#endif`

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M. S. Rakha, Ph.D.
Queen's University

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