DES加密解密算法

DES加密解密算法

// 仿射变换加解密.cpp : 定义控制台应用程序的入口点。
//

#include <stdio.h>
#include <conio.h>

static char key[10], key_a[5], code[8], key_b[5], temp[10], key_aa[8], key_bb[8], l[4], r[4], l_a[4], r_a[4], V[8] = { 0, 1, 0, 1, 0, 1, 0, 1 }, b[8];
char Code, CCode[100];
int p_a[10] = { 3, 5, 2, 7, 4, 10, 1, 9, 8, 6 };
int p_b[8] = { 6, 3, 7, 4, 8, 5, 10, 9 };
int S_a[4][4] = { 1, 0, 2, 3, 3, 2, 1, 0, 0, 2, 1, 3, 3, 1, 3, 2 };
int S_b[4][4] = { 0, 1, 2, 3, 2, 0, 1, 3, 3, 0, 1, 0, 2, 1, 0, 3 };
int IP_a[8] = { 2, 6, 3, 1, 4, 8, 5, 7 }, IP_b[8] = { 4, 1, 3, 5, 7, 2, 8, 6 };
int F_E[8] = { 4, 1, 2, 3, 2, 3, 4, 1 };
void C_code(char);
void coder(char a[10]);
void decoder(char a[10]);
void Sub_Key_Product(char a[10]);
void box(char a[4], int b[4][4]);
char XOR(char, char);
char ReCode(char a[8]);
void C_code_b(char);
void get_key();
void Coder(char a[100], char v[8]);
void Decoder(char a[100], char v[8]);
/**************************************************************************/
 int main()
{
    //int i;
    while (getchar() != ‘e‘)
    {
        //clrscr();
        printf("Please Enter The Text You Want to Code:\n");
        scanf("%s", CCode);
        Coder(CCode, V);
        printf("%s", CCode);
        printf("\n");
        Decoder(CCode, V);
        printf("%s", CCode);
    }
}
void Coder(char a[100], char v[8])           /*Make the text into coder*/
{
    int i, j;
    get_key();
    C_code(a[0]);
    for (i = 0; i<8; i++)
        code[i] = XOR(code[i], v[i]);
    Code = ReCode(code);
    coder(key);
    a[0] = Code;
    for (j = 1; j<100; j++)
    {
        C_code_b(a[j - 1]);
        C_code(a[j]);
        for (i = 0; i<8; i++)
            code[i] = XOR(code[i], b[i]);
        Code = ReCode(code);
        coder(key);
        a[j] = Code;
    }
}
void get_key()             /*Give the key to the computer*/
{
    int i;
    getch();
    printf("Please enter the key:");
    scanf("%s", key);
    for (i = 0; i<10; i++)
        key[i] -= 48;
}
void C_code_b(char m)          /*Make the number into binary */
{
    char i = 1, n = 64;
    if (m<0)
    {
        b[0] = 1;
        m = m + 128;
    }
    else
        b[0] = 0;
    while (i<8)
    {
        b[i] = m / n;
        m = m - n*b[i];
        n = n / 2;
        i++;
    }
}
void C_code(char m)
{
    char i = 1, n = 64;
    if (m<0)
    {
        code[0] = 1;
        m = m + 128;
    }
    else
        code[0] = 0;
    while (i<8)
    {
        code[i] = m / n;
        m = m - n*code[i];
        n = n / 2;
        i++;
    }
}
char XOR(char a, char b)
{
    if (a == b)
        return 0;
    else return 1;
}
char ReCode(char a[8])
{
    int i;
    for (i = 0; i<7; i++)
        a[i + 1] = 2 * a[i] + a[i + 1];
    return a[7];
}
void box(char a[4], int b[4][4])
{
    int t;
    t = b[a[0] * 2 + a[3]][a[1] * 2 + a[2]];
    temp[6] = t / 2;
    temp[7] = t % 2;
}
void Sub_Key_Product(char a[10])                /*Product the key word*/
{
    int i;
    for (i = 0; i<10; i++)
        temp[i] = a[p_a[i] - 1];/* m1 */
    for (i = 0; i<5; i++)
    {
        key_a[i] = temp[(i + 1) % 5];
        key_b[i] = temp[(i + 1) % 5 + 5];
    }
    i = 0;
    while (i<5)
    {
        temp[i] = key_a[i];
        i++;
    }
    while (i<10)
    {
        temp[i] = key_b[i - 5];
        i++;
    }/* m2 */
    for (i = 0; i<8; i++)
        key_aa[i] = temp[p_b[i] - 1];/* k1 */
    for (i = 0; i<5; i++)

    {
        key_a[i] = temp[(i + 2) % 5];
        key_b[i] = temp[(i + 2) % 5 + 5];
    } /* m2 移位 */
    i = 0;
    while (i<5)
    {
        temp[i] = key_a[i];
        i++;
    }
    while (i<10)
    {
        temp[i] = key_b[i - 5];
        i++;
    } /* m3 */
    for (i = 0; i<8; i++)
        key_bb[i] = temp[p_b[i] - 1];/* k2  */
}
void IP()
{
    int i;
    for (i = 0; i<8; i++)
        temp[i] = code[IP_a[i] - 1];
    for (i = 0; i<8; i++)
        code[i] = temp[i];
}
void de_IP()
{
    int i;
    for (i = 0; i<8; i++)
        temp[i] = code[IP_b[i] - 1];
    for (i = 0; i<8; i++)
        code[i] = temp[i];
}
void fk(char c_key[8])
{
    int i;
    for (i = 0; i<4; i++)
    {
        l[i] = code[i];
        r[i] = code[i + 4];
    }
    for (i = 0; i<8; i++)
        temp[i] = XOR(r[F_E[i] - 1], c_key[i]);/* 与key异或 */
    for (i = 0; i<4; i++)
    {
        l_a[i] = temp[i];
        r_a[i] = temp[i + 4];
    }
    box(l_a, S_a);/* S0 */
    temp[4] = temp[6];
    temp[5] = temp[7];
    box(r_a, S_b);/* S1 */
    temp[0] = temp[5];
    temp[1] = temp[7];
    temp[2] = temp[6];
    temp[3] = temp[4];/* P4 */
    for (i = 0; i<4; i++)
        l[i] = XOR(temp[i], l[i]);
    i = 0;
    while (i<4)
    {
        code[i] = l[i];
        i++;
    }
    while (i<8)
    {
        code[i] = r[i - 4];
        i++;
    }/* 合并 */
}
void SW()
{
    int i = 0;
    while (i<4)
    {
        code[i] = r[i];
        i++;
    }
    while (i<8)
    {
        code[i] = l[i - 4];
        i++;
    }/* SW */
}
void coder(char a[10])
{
    C_code(Code);
    IP();
    Sub_Key_Product(a);
    fk(key_aa);
    SW();
    fk(key_bb);
    de_IP();
    Code = ReCode(code);

}
void decoder(char a[10])
{
    C_code(Code);
    IP();
    Sub_Key_Product(a);
    fk(key_bb);
    SW();
    fk(key_aa);
    de_IP();
    Code = ReCode(code);

}
void Decoder(char a[100], char v[8])         /*Make the coder into text*/
{
    int i, j;
    get_key();
    Code = a[0];
    decoder(key);
    C_code(Code);
    for (i = 0; i<8; i++)
        code[i] = XOR(code[i], v[i]);
    C_code_b(a[0]);
    a[0] = ReCode(code);
    for (j = 1; j<100; j++)
    {
        Code = a[j];
        decoder(key);
        C_code(Code);
        for (i = 0; i<8; i++)
            code[i] = XOR(code[i], b[i]);
        C_code_b(a[j]);
        a[j] = ReCode(code);
    }
}