DES-Decryption.zip

#include<stdio.h> #include<stdlib.h> void IP(int plaintext[]);//初始置换，传进来的是64位明文数组 void InversePermutation(int cipher[]);//逆初始置换 void ExtendAndPermutation(int RIn[]);//扩展置换,输入RIn为48位，后面16位为空 void XOR_48(int xor[], int Ki[]);//XOR 48位 void SBox(int S[]);//输入S盒为48位 void Permutation(int Pin[]);//置换P，32位数组输入 void XOR_32(int L[],int xor[]);//二者均为32位,xor[]保存异或结果 void Round(int bits[], int Ki[]);//bits为64位输入，经过函数后改变值成为输出，Ki为第i轮的密钥,轮函数 void PC1(int key[]);//key为64位,后8位被处理成0，前56位为置换选择的结果 void RingShiftLeft(int input[], int k);//input为56位输入，k为当前轮数-1 void RingShiftRight(int input[], int k);//input为56位输入，k为当前轮数-1 void PC2(int key[]);//输入为56位密钥,前48位更改为48位密钥，后8位置0 void exchange_32(int mid[]);//输入为64位数组 typedef struct node{ int plain[64]; struct node *link; }LNode,*LinkList; int main() { int mid[64]; char Input[16]; int key[64]; int midkey[64]; int midkey_56[56]; int midkey_56_2[56]; int midkey_48[48]; char KEY[16]; int q = 0; int lunshu = 0; char ch; int res; int haha; int i; int i1; int k=0;//只在读取时用 int j=0; LinkList head = NULL, p = NULL, r,Plain = NULL,b,c; printf("请输入16进制密文与密钥，中间以空格分隔\n"); ch = getchar(); while (ch != ' ')//读取输入明文，16进制，转换为二进制储存于head链表中，每个链结点中有两个十六进制数，即64位二进制数 { for (i = 0; i < 16; i++)//16位输入 { Input[i] = ch; if ((' ' == ch) && (i!=15) )//如果不满足16位，也就是8位十六进制输入，以最后一位补全 { for (i = 8; i < 16; i++) Input[i] = Input[i - 1]; break; } ch = getchar(); } i = 0; k = 0; while (i < 16){//转换为2进制，暂存于mid[]中 switch (Input[i++]) { case '0':mid[k++] = 0; mid[k++] = 0; mid[k++] = 0; mid[k++] = 0; break; case '1':mid[k++] = 0; mid[k++] = 0; mid[k++] = 0; mid[k++] = 1; break; case '2':mid[k++] = 0; mid[k++] = 0; mid[k++] = 1; mid[k++] = 0; break; case '3':mid[k++] = 0; mid[k++] = 0; mid[k++] = 1; mid[k++] = 1; break; case '4':mid[k++] = 0; mid[k++] = 1; mid[k++] = 0; mid[k++] = 0; break; case '5':mid[k++] = 0; mid[k++] = 1; mid[k++] = 0; mid[k++] = 1; break; case '6':mid[k++] = 0; mid[k++] = 1; mid[k++] = 1; mid[k++] = 0; break; case '7':mid[k++] = 0; mid[k++] = 1; mid[k++] = 1; mid[k++] = 1; break; case '8':mid[k++] = 1; mid[k++] = 0; mid[k++] = 0; mid[k++] = 0; break; case '9':mid[k++] = 1; mid[k++] = 0; mid[k++] = 0; mid[k++] = 1; break; case 'a':mid[k++] = 1; mid[k++] = 0; mid[k++] = 1; mid[k++] = 0; break; case 'b':mid[k++] = 1; mid[k++] = 0; mid[k++] = 1; mid[k++] = 1; break; case 'c':mid[k++] = 1; mid[k++] = 1; mid[k++] = 0; mid[k++] = 0; break; case 'd':mid[k++] = 1; mid[k++] = 1; mid[k++] = 0; mid[k++] = 1; break; case 'e':mid[k++] = 1; mid[k++] = 1; mid[k++] = 1; mid[k++] = 0; break; case 'f':mid[k++] = 1; mid[k++] = 1; mid[k++] = 1; mid[k++] = 1; break; default:break; } } p = (LinkList)malloc(sizeof(LNode)); for (i = 0; i < 64; i++) { p->plain[i] = mid[i]; } p->link = NULL; if (head == NULL) head = p; else r->link = p; r = p; } do{//吃掉空格 ch = getchar(); } while (ch == ' '); //get key while (ch != '\n')//读取输入密钥，16进制 { for (i = 0; i < 16; i++)//16位输入 { KEY[i] = ch; ch = getchar(); } i = 0; k = 0; while (i < 16){//转换为2进制，暂存于mid[]中 switch (KEY[i++]) { case '0':key[k++] = 0; key[k++] = 0; key[k++] = 0; key[k++] = 0; break; case '1':key[k++] = 0; key[k++] = 0; key[k++] = 0; key[k++] = 1; break; case '2':key[k++] = 0; key[k++] = 0; key[k++] = 1; key[k++] = 0; break; case '3':key[k++] = 0; key[k++] = 0; key[k++] = 1; key[k++] = 1; break; case '4':key[k++] = 0; key[k++] = 1; key[k++] = 0; key[k++] = 0; break; case '5':key[k++] = 0; key[k++] = 1; key[k++] = 0; key[k++] = 1; break; case '6':key[k++] = 0; key[k++] = 1; key[k++] = 1; key[k++] = 0; break; case '7':key[k++] = 0; key[k++] = 1; key[k++] = 1; key[k++] = 1; break; case '8':key[k++] = 1; key[k++] = 0; key[k++] = 0; key[k++] = 0; break; case '9':key[k++] = 1; key[k++] = 0; key[k++] = 0; key[k++] = 1; break; case 'a':key[k++] = 1; key[k++] = 0; key[k++] = 1; key[k++] = 0; break; case 'b':key[k++] = 1; key[k++] = 0; key[k++] = 1; key[k++] = 1; break; case 'c':key[k++] = 1; key[k++] = 1; key[k++] = 0; key[k++] = 0; break; case 'd':key[k++] = 1; key[k++] = 1; key[k++] = 0; key[k++] = 1; break; case 'e':key[k++] = 1; key[k++] = 1; key[k++] = 1; key[k++] = 0; break; case 'f':key[k++] = 1; key[k++] = 1; key[k++] = 1; key[k++] = 1; break; default:break; } } } p = head; while (p != NULL) { for (i1 = 0; i1 < 64; i1++) { mid[i1] = p->plain[i1]; } for (i1 = 0; i1 < 64; i1++) { midkey[i1] = key[i1]; } IP(mid);//初始置换 PC1(midkey);//置换选择1,midkey前56位有效 for (q = 0; q < 56; q++) midkey_56[q] = midkey[q]; for(lunshu = 0;lunshu < 16; lunshu++) RingShiftLeft(midkey_56, lunshu); for (lunshu = 0; lunshu < 16; lunshu++)//16轮轮函数处理 { for (q = 0; q < 56; q++)//将循环左移结果拷贝，留着原来的结果midkey_56进行下一次循环左移 midkey_56_2[q] = midkey_56[q]; PC2(midkey_56_2); for (q = 0; q < 48; q++)//得到48位密钥 midkey_48[q] = midkey_56_2[q]; Round(mid, midkey_48); RingShiftRight(midkey_56, lunshu); } exchange_32(mid); InversePermutation(mid); b = (LinkList)malloc(sizeof(LNode)); for (i = 0; i < 64; i++) { b->plain[i] = mid[i]; } b->link = NULL; if (Plain == NULL) Plain = b; else c->link = b; c = b; p = p->link; } b = Plain; while (b != NULL) { for (i = 0; i < 64; ) { haha = 8; res = 0; for (k = 0; k < 4; k++) { res = res + haha*(b->plain[i++]); haha = haha / 2; } switch (res)//输出为16进制 { case 0:printf("0"); break; case 1:printf("1"); break; case 2:printf("2"); break; case 3:printf("3"); break; case 4:printf("4"); break; case 5:printf("5"); break; case 6:printf("6"); break; case 7:printf("7"); break; case 8:printf("8"); break; case 9:printf("9"); break; case 10:printf("a"); break; case 11:printf("b"); break; case 12:printf("c"); break; case 13:printf("d"); break; case 14:printf("e"); break; case 15:printf("f"); break; } } b = b->link; } printf("\n"); return 0; } void exchange_32(int mid[]) { int mid1[32]; int i; for(i = 0;i<32;i++) { mid1[i] = mid[i]; } for(i = 32;i<64;i++) { mid[i-32]=mid[i]; } for(i = 32;i<64;i++) { mid[i] = mid1[i-32]; } } void IP(int plaintext[])//初始置换，传进来的是64位明文数组 { int mid[8][8]; int i = 0; int j = 0; int k = 0; for (i = 7; i >= 0; i--) { mid[4][i] = plaintext[j++]; mid[0][i] = plaintext[j++]; mid[5][i] = plaintext[j++]; mid[1][i] = plaintext[j++]; mid[6][i] = plaintext[j++]; mid[2][i] = plaintext[j++]; mid[7][i] = plaintext[j++]; mid[3][i] = plaintext[j++]; if (j == 64) break; } j = 0; for (i = 0; i < 8; i++) { for (k = 0; k < 8; k++) { plaintext[j++] = mid[i][k]; } } } void InversePermutation(int cipher[])//逆初始置换 { int mid[8][8]; int i = 0; int j = 0; int k = 0; for (i = 1; i != 8; i = (i + 2) % 9)//i做列 { for (j = 7; j >= 0; j--)//j做行 { mid[j][i] = cipher[k++]; } } k = 0; for (j = 0; j < 8; j++)//j做行 { for (i = 0; i < 8; i++)//i做列 { cipher[k++] = mid[j][i]; } } } void ExtendAndPermutation(int RIn[])//扩展置换,输入RIn为48位，后面16位为空 { int mid[8][6]; int i = 0; int j = 0; int p = 0; for (i = 0; i < 8; i++)//行 { for (j = 1; j <