用C語言實現DES算法

本DES算法，使用了效率很高的C完成。目前，國內知名企業的POS終端中，單DES算法，均是采用這個函數完成。函數經本站驗證過，可以放心使用。
#include "stdafx.h"
int des(unsigned char *source,unsigned char * dest,unsigned char * inkey, int flg);
int _tmain(int argc, _TCHAR* argv[])
{

unsigned char s[65]="DES算法是這樣工作的：如Mode為加密，則用Key 去把數據Data進行加abc";
unsigned char d[65]={0};
unsigned char k[11]="adsss";
unsigned char m[65]={0};
for(int i =0;i<8;i++)
{
??? des(&s[8*i],&d[8*i],k,0);
}
for(int i =0;i<8;i++)
{
??? des(&d[8*i],&m[8*i],k,1);
}
//des(s,d,k,0);
//des(d,m,k2,1);
//printf(d);

char i;
scanf("%c",&i);
return 0;
}

/* ============================================================
des()
Description: DES algorithm,do encript or descript.
============================================================ */
int des(unsigned char *source,unsigned char * dest,unsigned char * inkey, int flg)
{
unsigned char bufout[64],
kwork[56], worka[48], kn[48], buffer[64], key[64],
nbrofshift, temp1, temp2;
int valindex;
register i, j, k, iter;
/* INITIALIZE THE TABLES */
/* Table - s1 */
static unsigned char s1[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 };
/* Table - s2 */
static unsigned char s2[4][16] = {
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 };
/* Table - s3 */
static unsigned char s3[4][16] = {
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 };
/* Table - s4 */
static unsigned char s4[4][16] = {
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 };
/* Table - s5 */
static unsigned char s5[4][16] = {
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 };
/* Table - s6 */
static unsigned char s6[4][16] = {
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 };
/* Table - s7 */
static unsigned char s7[4][16] = {
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 };
/* Table - s8 */
static unsigned char s8[4][16] = {
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 };

/* Table - Shift */
static unsigned char shift[16] = {
1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };

/* Table - Binary */
static unsigned char binary[64] = {
0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1,
0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1,
1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1,
1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1 };
/* MAIN PROCESS */
/* Convert from 64-bit key into 64-byte key */
for (i = 0; i < 8; i++) {
key[8*i] = ((j = *(inkey + i)) / 128) % 2;
key[8*i+1] = (j / 64) % 2;
key[8*i+2] = (j / 32) % 2;
key[8*i+3] = (j / 16) % 2;
key[8*i+4] = (j / 8) % 2;
key[8*i+5] = (j / 4) % 2;
key[8*i+6] = (j / 2) % 2;
key[8*i+7] = j % 2;
}
/* Convert from 64-bit data into 64-byte data */
for (i = 0; i < 8; i++) {
buffer[8*i] = ((j = *(source + i)) / 128) % 2;
buffer[8*i+1] = (j / 64) % 2;
buffer[8*i+2] = (j / 32) % 2;
buffer[8*i+3] = (j / 16) % 2;
buffer[8*i+4] = (j / 8) % 2;
buffer[8*i+5] = (j / 4) % 2;
buffer[8*i+6] = (j / 2) % 2;
buffer[8*i+7] = j % 2;
}
/* Initial Permutation of Data */
bufout[ 0] = buffer[57];
bufout[ 1] = buffer[49];
bufout[ 2] = buffer[41];
bufout[ 3] = buffer[33];
bufout[ 4] = buffer[25];
bufout[ 5] = buffer[17];
bufout[ 6] = buffer[ 9];
bufout[ 7] = buffer[ 1];
bufout[ 8] = buffer[59];
bufout[ 9] = buffer[51];
bufout[10] = buffer[43];
bufout[11] = buffer[35];
bufout[12] = buffer[27];
bufout[13] = buffer[19];
bufout[14] = buffer[11];
bufout[15] = buffer[ 3];
bufout[16] = buffer[61];
bufout[17] = buffer[53];
bufout[18] = buffer[45];
bufout[19] = buffer[37];
bufout[20] = buffer[29];
bufout[21] = buffer[21];
bufout[22] = buffer[13];
bufout[23] = buffer[ 5];
bufout[24] = buffer[63];
bufout[25] = buffer[55];
bufout[26] = buffer[47];
bufout[27] = buffer[39];
bufout[28] = buffer[31];
bufout[29] = buffer[23];
bufout[30] = buffer[15];
bufout[31] = buffer[ 7];
bufout[32] = buffer[56];
bufout[33] = buffer[48];
bufout[34] = buffer[40];
bufout[35] = buffer[32];
bufout[36] = buffer[24];
bufout[37] = buffer[16];
bufout[38] = buffer[ 8];
bufout[39] = buffer[ 0];
bufout[40] = buffer[58];
bufout[41] = buffer[50];
bufout[42] = buffer[42];
bufout[43] = buffer[34];
bufout[44] = buffer[26];
bufout[45] = buffer[18];
bufout[46] = buffer[10];
bufout[47] = buffer[ 2];
bufout[48] = buffer[60];
bufout[49] = buffer[52];
bufout[50] = buffer[44];
bufout[51] = buffer[36];
bufout[52] = buffer[28];
bufout[53] = buffer[20];
bufout[54] = buffer[12];
bufout[55] = buffer[ 4];
bufout[56] = buffer[62];
bufout[57] = buffer[54];
bufout[58] = buffer[46];
bufout[59] = buffer[38];
bufout[60] = buffer[30];
bufout[61] = buffer[22];
bufout[62] = buffer[14];
bufout[63] = buffer[ 6];
/* Initial Permutation of Key */
kwork[ 0] = key[56];
kwork[ 1] = key[48];
kwork[ 2] = key[40];
kwork[ 3] = key[32];
kwork[ 4] = key[24];
kwork[ 5] = key[16];
kwork[ 6] = key[ 8];
kwork[ 7] = key[ 0];
kwork[ 8] = key[57];
kwork[ 9] = key[49];
kwork[10] = key[41];
kwork[11] = key[33];
kwork[12] = key[25];
kwork[13] = key[17];
kwork[14] = key[ 9];
kwork[15] = key[ 1];
kwork[16] = key[58];
kwork[17] = key[50];
kwork[18] = key[42];
kwork[19] = key[34];
kwork[20] = key[26];
kwork[21] = key[18];
kwork[22] = key[10];
kwork[23] = key[ 2];
kwork[24] = key[59];
kwork[25] = key[51];
kwork[26] = key[43];
kwork[27] = key[35];
kwork[28] = key[62];
kwork[29] = key[54];
kwork[30] = key[46];
kwork[31] = key[38];
kwork[32] = key[30];
kwork[33] = key[22];
kwork[34] = key[14];
kwork[35] = key[ 6];
kwork[36] = key[61];
kwork[37] = key[53];
kwork[38] = key[45];
kwork[39] = key[37];
kwork[40] = key[29];
kwork[41] = key[21];
kwork[42] = key[13];
kwork[43] = key[ 5];
kwork[44] = key[60];
kwork[45] = key[52];
kwork[46] = key[44];
kwork[47] = key[36];
kwork[48] = key[28];
kwork[49] = key[20];
kwork[50] = key[12];
kwork[51] = key[ 4];
kwork[52] = key[27];
kwork[53] = key[19];
kwork[54] = key[11];
kwork[55] = key[ 3];
/* 16 Iterations */
for (iter = 1; iter < 17; iter++) {
for (i = 0; i < 32; i++)
{
??? buffer[i] = bufout[32+i];
}
/* Calculation of F(R, K) */
/* Permute - E */
worka[ 0] = buffer[31];
worka[ 1] = buffer[ 0];
worka[ 2] = buffer[ 1];
worka[ 3] = buffer[ 2];
worka[ 4] = buffer[ 3];
worka[ 5] = buffer[ 4];
worka[ 6] = buffer[ 3];
worka[ 7] = buffer[ 4];
worka[ 8] = buffer[ 5];
worka[ 9] = buffer[ 6];
worka[10] = buffer[ 7];
worka[11] = buffer[ 8];
worka[12] = buffer[ 7];
worka[13] = buffer[ 8];
worka[14] = buffer[ 9];
worka[15] = buffer[10];
worka[16] = buffer[11];
worka[17] = buffer[12];
worka[18] = buffer[11];
worka[19] = buffer[12];
worka[20] = buffer[13];
worka[21] = buffer[14];
worka[22] = buffer[15];
worka[23] = buffer[16];
worka[24] = buffer[15];
worka[25] = buffer[16];
worka[26] = buffer[17];
worka[27] = buffer[18];
worka[28] = buffer[19];
worka[29] = buffer[20];
worka[30] = buffer[19];
worka[31] = buffer[20];
worka[32] = buffer[21];
worka[33] = buffer[22];
worka[34] = buffer[23];
worka[35] = buffer[24];
worka[36] = buffer[23];
worka[37] = buffer[24];
worka[38] = buffer[25];
worka[39] = buffer[26];
worka[40] = buffer[27];
worka[41] = buffer[28];
worka[42] = buffer[27];
worka[43] = buffer[28];
worka[44] = buffer[29];
worka[45] = buffer[30];
worka[46] = buffer[31];
worka[47] = buffer[ 0];
/* KS Function Begin */
if (flg) {
nbrofshift = shift[iter-1];
for (i = 0; i < (int) nbrofshift; i++) {
??? temp1 = kwork[0];
??? temp2 = kwork[28];
??? for (j = 0; j < 27; j++) {
???? kwork[j] = kwork[j+1];
???? kwork[j+28] = kwork[j+29];
??? }
??? kwork[27] = temp1;
??? kwork[55] = temp2;
}
} else if (iter > 1) {
nbrofshift = shift[17-iter];
for (i = 0; i < (int) nbrofshift; i++) {
??? temp1 = kwork[27];
??? temp2 = kwork[55];
??? for (j = 27; j > 0; j--) {
???? kwork[j] = kwork[j-1];
???? kwork[j+28] = kwork[j+27];
??? }
??? kwork[0] = temp1;
??? kwork[28] = temp2;
}
}
/* Permute kwork - PC2 */
kn[ 0] = kwork[13];
kn[ 1] = kwork[16];
kn[ 2] = kwork[10];
kn[ 3] = kwork[23];
kn[ 4] = kwork[ 0];
kn[ 5] = kwork[ 4];
kn[ 6] = kwork[ 2];
kn[ 7] = kwork[27];
kn[ 8] = kwork[14];
kn[ 9] = kwork[ 5];
kn[10] = kwork[20];
kn[11] = kwork[ 9];
kn[12] = kwork[22];
kn[13] = kwork[18];
kn[14] = kwork[11];
kn[15] = kwork[ 3];
kn[16] = kwork[25];
kn[17] = kwork[ 7];
kn[18] = kwork[15];
kn[19] = kwork[ 6];
kn[20] = kwork[26];
kn[21] = kwork[19];
kn[22] = kwork[12];
kn[23] = kwork[ 1];
kn[24] = kwork[40];
kn[25] = kwork[51];
kn[26] = kwork[30];
kn[27] = kwork[36];
kn[28] = kwork[46];
kn[29] = kwork[54];
kn[30] = kwork[29];
kn[31] = kwork[39];
kn[32] = kwork[50];
kn[33] = kwork[44];
kn[34] = kwork[32];
kn[35] = kwork[47];
kn[36] = kwork[43];
kn[37] = kwork[48];
kn[38] = kwork[38];
kn[39] = kwork[55];
kn[40] = kwork[33];
kn[41] = kwork[52];
kn[42] = kwork[45];
kn[43] = kwork[41];
kn[44] = kwork[49];
kn[45] = kwork[35];
kn[46] = kwork[28];
kn[47] = kwork[31];
/* KS Function End */
/* worka XOR kn */
for (i = 0; i < 48; i++)
worka[i] = worka[i] ^ kn[i];
/* 8 s-functions */
valindex = s1[2*worka[ 0]+worka[ 5]]
[2*(2*(2*worka[ 1]+worka[ 2])+
worka[ 3])+worka[ 4]];
valindex = valindex * 4;
kn[ 0] = binary[0+valindex];
kn[ 1] = binary[1+valindex];
kn[ 2] = binary[2+valindex];
kn[ 3] = binary[3+valindex];
valindex = s2[2*worka[ 6]+worka[11]]
[2*(2*(2*worka[ 7]+worka[ 8])+
worka[ 9])+worka[10]];
valindex = valindex * 4;
kn[ 4] = binary[0+valindex];
kn[ 5] = binary[1+valindex];
kn[ 6] = binary[2+valindex];
kn[ 7] = binary[3+valindex];
valindex = s3[2*worka[12]+worka[17]]
[2*(2*(2*worka[13]+worka[14])+
worka[15])+worka[16]];
valindex = valindex * 4;
kn[ 8] = binary[0+valindex];
kn[ 9] = binary[1+valindex];
kn[10] = binary[2+valindex];
kn[11] = binary[3+valindex];
valindex = s4[2*worka[18]+worka[23]]
[2*(2*(2*worka[19]+worka[20])+
worka[21])+worka[22]];
valindex = valindex * 4;
kn[12] = binary[0+valindex];
kn[13] = binary[1+valindex];
kn[14] = binary[2+valindex];
kn[15] = binary[3+valindex];
valindex = s5[2*worka[24]+worka[29]]
[2*(2*(2*worka[25]+worka[26])+
worka[27])+worka[28]];
valindex = valindex * 4;
kn[16] = binary[0+valindex];
kn[17] = binary[1+valindex];
kn[18] = binary[2+valindex];
kn[19] = binary[3+valindex];
valindex = s6[2*worka[30]+worka[35]]
[2*(2*(2*worka[31]+worka[32])+
worka[33])+worka[34]];
valindex = valindex * 4;
kn[20] = binary[0+valindex];
kn[21] = binary[1+valindex];
kn[22] = binary[2+valindex];
kn[23] = binary[3+valindex];
valindex = s7[2*worka[36]+worka[41]]
[2*(2*(2*worka[37]+worka[38])+
worka[39])+worka[40]];
valindex = valindex * 4;
kn[24] = binary[0+valindex];
kn[25] = binary[1+valindex];
kn[26] = binary[2+valindex];
kn[27] = binary[3+valindex];
valindex = s8[2*worka[42]+worka[47]]
[2*(2*(2*worka[43]+worka[44])+
worka[45])+worka[46]];
valindex = valindex * 4;
kn[28] = binary[0+valindex];
kn[29] = binary[1+valindex];
kn[30] = binary[2+valindex];
kn[31] = binary[3+valindex];
/* Permute - P */
worka[ 0] = kn[15];
worka[ 1] = kn[ 6];
worka[ 2] = kn[19];
worka[ 3] = kn[20];
worka[ 4] = kn[28];
worka[ 5] = kn[11];
worka[ 6] = kn[27];
worka[ 7] = kn[16];
worka[ 8] = kn[ 0];
worka[ 9] = kn[14];
worka[10] = kn[22];
worka[11] = kn[25];
worka[12] = kn[ 4];
worka[13] = kn[17];
worka[14] = kn[30];
worka[15] = kn[ 9];
worka[16] = kn[ 1];
worka[17] = kn[ 7];
worka[18] = kn[23];
worka[19] = kn[13];
worka[20] = kn[31];
worka[21] = kn[26];
worka[22] = kn[ 2];
worka[23] = kn[ 8];
worka[24] = kn[18];
worka[25] = kn[12];
worka[26] = kn[29];
worka[27] = kn[ 5];
worka[28] = kn[21];
worka[29] = kn[10];
worka[30] = kn[ 3];
worka[31] = kn[24];
/* bufout XOR worka */
for (i = 0; i < 32; i++) {
??? bufout[i+32] = bufout[i] ^ worka[i];
??? bufout[i] = buffer[i];
}
} /* End of Iter */
/* Prepare Output */
for (i = 0; i < 32; i++) {
??? j = bufout[i];
??? bufout[i] = bufout[32+i];
??? bufout[32+i] = j;
}
/* Inverse Initial Permutation */
buffer[ 0] = bufout[39];
buffer[ 1] = bufout[ 7];
buffer[ 2] = bufout[47];
buffer[ 3] = bufout[15];
buffer[ 4] = bufout[55];
buffer[ 5] = bufout[23];
buffer[ 6] = bufout[63];
buffer[ 7] = bufout[31];
buffer[ 8] = bufout[38];
buffer[ 9] = bufout[ 6];
buffer[10] = bufout[46];
buffer[11] = bufout[14];
buffer[12] = bufout[54];
buffer[13] = bufout[22];
buffer[14] = bufout[62];
buffer[15] = bufout[30];
buffer[16] = bufout[37];
buffer[17] = bufout[ 5];
buffer[18] = bufout[45];
buffer[19] = bufout[13];
buffer[20] = bufout[53];
buffer[21] = bufout[21];
buffer[22] = bufout[61];
buffer[23] = bufout[29];
buffer[24] = bufout[36];
buffer[25] = bufout[ 4];
buffer[26] = bufout[44];
buffer[27] = bufout[12];
buffer[28] = bufout[52];
buffer[29] = bufout[20];
buffer[30] = bufout[60];
buffer[31] = bufout[28];
buffer[32] = bufout[35];
buffer[33] = bufout[ 3];
buffer[34] = bufout[43];
buffer[35] = bufout[11];
buffer[36] = bufout[51];
buffer[37] = bufout[19];
buffer[38] = bufout[59];
buffer[39] = bufout[27];
buffer[40] = bufout[34];
buffer[41] = bufout[ 2];
buffer[42] = bufout[42];
buffer[43] = bufout[10];
buffer[44] = bufout[50];
buffer[45] = bufout[18];
buffer[46] = bufout[58];
buffer[47] = bufout[26];
buffer[48] = bufout[33];
buffer[49] = bufout[ 1];
buffer[50] = bufout[41];
buffer[51] = bufout[ 9];
buffer[52] = bufout[49];
buffer[53] = bufout[17];
buffer[54] = bufout[57];
buffer[55] = bufout[25];
buffer[56] = bufout[32];
buffer[57] = bufout[ 0];
buffer[58] = bufout[40];
buffer[59] = bufout[ 8];
buffer[60] = bufout[48];
buffer[61] = bufout[16];
buffer[62] = bufout[56];
buffer[63] = bufout[24];
j = 0;
for (i = 0; i < 8; i++) {
??? *(dest + i) = 0x00;
??? for (k = 0; k < 7; k++)
??? *(dest + i) = ((*(dest + i)) + buffer[j+k]) * 2;
??? *(dest + i) = *(dest + i) + buffer[j+7];
??? j += 8;
}
return 0;
}