[C/C++ 演算法]-純C的DES加解密
[C/C++ 演算法]-純C的DES加解密
資料來源: http://blog.csdn.net/lisonglisonglisong/article/details/41777413
http://ouyangjia7.iteye.com/blog/478024
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#include <stdio.h> #include <memory.h> #include <time.h> #include <stdlib.h>
#define PLAIN_FILE_OPEN_ERROR –1 #define KEY_FILE_OPEN_ERROR –2 #define CIPHER_FILE_OPEN_ERROR –3 #define OK 1
typedefchar ElemType;
//初始置換表IP int IP_Table[64]={ 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, 56,48,40,32,24,16,8,0, 58,50,42,34,26,18,10,2, 60,52,44,36,28,20,12,4, 62,54,46,38,30,22,14,6}; //逆初始置換表IP^-1 int IP_1_Table[64]={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, 32,0,40,8,48,16,56,24};
//擴充置換表E int E_Table[48]={31,0,1,2,3,4, 3, 4,5,6,7,8, 7, 8,9,10,11,12, 11,12,13,14,15,16, 15,16,17,18,19,20, 19,20,21,22,23,24, 23,24,25,26,27,28, 27,28,29,30,31,0};
//置換函數P int P_Table[32]={15,6,19,20,28,11,27,16, 0,14,22,25,4,17,30,9, 1,7,23,13,31,26,2,8, 18,12,29,5,21,10,3,24};
//S盒 int S[8][4][16]=//S1 {{{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}}, //S2 {{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}}, //S3 {{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}}, //S4 {{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}}, //S5 {{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}}, //S6 {{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}}, //S7 {{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}}, //S8 {{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}}}; //置換選擇1 int PC_1[56]={56,48,40,32,24,16,8, 0,57,49,41,33,25,17, 9,1,58,50,42,34,26, 18,10,2,59,51,43,35, 62,54,46,38,30,22,14, 6,61,53,45,37,29,21, 13,5,60,52,44,36,28, 20,12,4,27,19,11,3};
//置換選擇2 int PC_2[48]={13,16,10,23,0,4,2,27, 14,5,20,9,22,18,11,3, 25,7,15,6,26,19,12,1, 40,51,30,36,46,54,29,39, 50,44,32,46,43,48,38,55, 33,52,45,41,49,35,28,31};
//對左移次數的規定 int MOVE_TIMES[16]={1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};
int ByteToBit(ElemType ch,ElemType bit[8]); int BitToByte(ElemType bit[8],ElemType *ch); int Char8ToBit64(ElemType ch[8],ElemType bit[64]); int Bit64ToChar8(ElemType bit[64],ElemType ch[8]); int DES_MakeSubKeys(ElemType key[64],ElemType subKeys[16][48]); int DES_PC1_Transform(ElemType key[64], ElemType tempbts[56]); int DES_PC2_Transform(ElemType key[56], ElemType tempbts[48]); int DES_ROL(ElemType data[56],inttime); int DES_IP_Transform(ElemType data[64]); int DES_IP_1_Transform(ElemType data[64]); int DES_E_Transform(ElemType data[48]); int DES_P_Transform(ElemType data[32]); int DES_SBOX(ElemType data[48]); int DES_XOR(ElemType R[48], ElemType L[48],int count); int DES_Swap(ElemType left[32],ElemType right[32]); int DES_EncryptBlock(ElemType plainBlock[8], ElemType subKeys[16][48], ElemType cipherBlock[8]); int DES_DecryptBlock(ElemType cipherBlock[8], ElemType subKeys[16][48], ElemType plainBlock[8]); int DES_Encrypt(char*plainFile,char*keyStr,char*cipherFile); int DES_Decrypt(char*cipherFile,char*keyStr,char*plainFile);
//位元組轉換成二進位 int ByteToBit(ElemType ch, ElemType bit[8]){ int cnt; for(cnt =0;cnt <8; cnt++){ *(bit+cnt)=(ch>>cnt)&1; } return0; }
//二進位轉換成位元組 int BitToByte(ElemType bit[8],ElemType *ch){ int cnt; for(cnt =0;cnt <8; cnt++){ *ch |=*(bit + cnt)<<cnt; } return0; }
//將長度為8的字串轉為二進位位元串 int Char8ToBit64(ElemType ch[8],ElemType bit[64]){ int cnt; for(cnt =0; cnt <8; cnt++){ ByteToBit(*(ch+cnt),bit+(cnt<<3)); } return0; }
//將二進位位元串轉為長度為8的字串 int Bit64ToChar8(ElemType bit[64],ElemType ch[8]){ int cnt; memset(ch,0,8); for(cnt =0; cnt <8; cnt++){ BitToByte(bit+(cnt<<3),ch+cnt); } return0; }
//生成子金鑰 int DES_MakeSubKeys(ElemType key[64],ElemType subKeys[16][48]){ ElemType temp[56]; int cnt; DES_PC1_Transform(key,temp);//PC1置換 for(cnt =0; cnt <16; cnt++){//16輪跌代，產生16個子金鑰 DES_ROL(temp,MOVE_TIMES[cnt]);//迴圈左移 DES_PC2_Transform(temp,subKeys[cnt]);//PC2置換，產生子金鑰 } return0; }
//金鑰置換1 int DES_PC1_Transform(ElemType key[64], ElemType tempbts[56]){ int cnt; for(cnt =0; cnt <56; cnt++){ tempbts[cnt]= key[PC_1[cnt]]; } return0; }
//金鑰置換2 int DES_PC2_Transform(ElemType key[56], ElemType tempbts[48]){ int cnt; for(cnt =0; cnt <48; cnt++){ tempbts[cnt]= key[PC_2[cnt]]; } return0; }
//迴圈左移 int DES_ROL(ElemType data[56],inttime){ ElemType temp[56];
//保��將要迴圈移動到右邊的位 memcpy(temp,data,time); memcpy(temp+time,data+28,time);
//前28位移動 memcpy(data,data+time,28–time); memcpy(data+28–time,temp,time);
//後28位移動 memcpy(data+28,data+28+time,28–time); memcpy(data+56–time,temp+time,time);
return0; }
//IP置換 int DES_IP_Transform(ElemType data[64]){ int cnt; ElemType temp[64]; for(cnt =0; cnt <64; cnt++){ temp[cnt]= data[IP_Table[cnt]]; } memcpy(data,temp,64); return0; }
//IP逆置換 int DES_IP_1_Transform(ElemType data[64]){ int cnt; ElemType temp[64]; for(cnt =0; cnt <64; cnt++){ temp[cnt]= data[IP_1_Table[cnt]]; } memcpy(data,temp,64); return0; }
//擴展置換 int DES_E_Transform(ElemType data[48]){ int cnt; ElemType temp[48]; for(cnt =0; cnt <48; cnt++){ temp[cnt]= data[E_Table[cnt]]; } memcpy(data,temp,48); return0; }
//P置換 int DES_P_Transform(ElemType data[32]){ int cnt; ElemType temp[32]; for(cnt =0; cnt <32; cnt++){ temp[cnt]= data[P_Table[cnt]]; } memcpy(data,temp,32); return0; }
//異或 int DES_XOR(ElemType R[48], ElemType L[48],int count){ int cnt; for(cnt =0; cnt < count; cnt++){ R[cnt]^= L[cnt]; } return0; }
//S盒置換 int DES_SBOX(ElemType data[48]){ int cnt; int line,row,output; int cur1,cur2; for(cnt =0; cnt <8; cnt++){ cur1 = cnt*6; cur2 = cnt<<2;
//計算在S盒中的行與列 line =(data[cur1]<<1)+ data[cur1+5]; row =(data[cur1+1]<<3)+(data[cur1+2]<<2) +(data[cur1+3]<<1)+ data[cur1+4]; output = S[cnt][line][row];
//化為2進制 data[cur2]=(output&0X08)>>3; data[cur2+1]=(output&0X04)>>2; data[cur2+2]=(output&0X02)>>1; data[cur2+3]= output&0x01; } return0; }
//交換 int DES_Swap(ElemType left[32], ElemType right[32]){ ElemType temp[32]; memcpy(temp,left,32); memcpy(left,right,32); memcpy(right,temp,32); return0; }
//加密單個分組 int DES_EncryptBlock(ElemType plainBlock[8], ElemType subKeys[16][48], ElemType cipherBlock[8]){ ElemType plainBits[64]; ElemType copyRight[48]; int cnt;
Char8ToBit64(plainBlock,plainBits); //初始置換（IP置換） DES_IP_Transform(plainBits);
//16輪反覆運算 for(cnt =0; cnt <16; cnt++){ memcpy(copyRight,plainBits+32,32); //將右半部分進行擴展置換，從32位擴展到48位 DES_E_Transform(copyRight); //將右半部分與子金鑰進行異或操作 DES_XOR(copyRight,subKeys[cnt],48); //異或結果進入S盒，輸出32位結果 DES_SBOX(copyRight); //P置換 DES_P_Transform(copyRight); //將��文左半部分與右半部分進行異或 DES_XOR(plainBits,copyRight,32); if(cnt !=15){ //最終完成左右部的交換 DES_Swap(plainBits,plainBits+32); } } //逆初始置換（IP^1置換） DES_IP_1_Transform(plainBits); Bit64ToChar8(plainBits,cipherBlock); return0; }
//解密單個分組 int DES_DecryptBlock(ElemType cipherBlock[8], ElemType subKeys[16][48],ElemType plainBlock[8]){ ElemType cipherBits[64]; ElemType copyRight[48]; int cnt;
Char8ToBit64(cipherBlock,cipherBits); //初始置換（IP置換） DES_IP_Transform(cipherBits);
//16輪反覆運算 for(cnt =15; cnt >=0; cnt–){ memcpy(copyRight,cipherBits+32,32); //將右半部分進行擴展置換，從32位擴展到48位 DES_E_Transform(copyRight); //將右半部分與子金鑰進行異或操作 DES_XOR(copyRight,subKeys[cnt],48); //異或結果進入S盒，輸出32位結果 DES_SBOX(copyRight); //P置換 DES_P_Transform(copyRight); //將��文左半部分與右半部分進行異或 DES_XOR(cipherBits,copyRight,32); if(cnt !=0){ //最終完成左右部的交換 DES_Swap(cipherBits,cipherBits+32); } } //逆初始置換（IP^1置換） DES_IP_1_Transform(cipherBits); Bit64ToChar8(cipherBits,plainBlock); return0; }
//加密檔 int DES_Encrypt(char*plainFile,char*keyStr,char*cipherFile){ FILE*plain,*cipher; int count; ElemType plainBlock[8],cipherBlock[8],keyBlock[8]; ElemType bKey[64]; ElemType subKeys[16][48]; if((plain =fopen(plainFile,“rb“))==NULL){ return PLAIN_FILE_OPEN_ERROR; } if((cipher =fopen(cipherFile,“wb“))==NULL){ return CIPHER_FILE_OPEN_ERROR; } //設置金鑰 memcpy(keyBlock,keyStr,8); //將金鑰轉換為二進位流 Char8ToBit64(keyBlock,bKey); //生成子金鑰 DES_MakeSubKeys(bKey,subKeys);
while(!feof(plain)){ //每次讀8個位元組，並返回成功讀取的位元組數 if((count =fread(plainBlock,sizeof(char),8,plain))==8){ DES_EncryptBlock(plainBlock,subKeys,cipherBlock); fwrite(cipherBlock,sizeof(char),8,cipher); } } if(count){ //填充 memset(plainBlock + count,‘\0’,7– count); //最後一個字元保��包括最後一個字元在內的所填充的字元數量 plainBlock[7]=8– count; DES_EncryptBlock(plainBlock,subKeys,cipherBlock); fwrite(cipherBlock,sizeof(char),8,cipher); } fclose(plain); fclose(cipher); return OK; }
//解密文件 int DES_Decrypt(char*cipherFile,char*keyStr,char*plainFile){ FILE*plain,*cipher; int count,times =0; long fileLen; ElemType plainBlock[8],cipherBlock[8],keyBlock[8]; ElemType bKey[64]; ElemType subKeys[16][48]; if((cipher =fopen(cipherFile,“rb“))==NULL){ return CIPHER_FILE_OPEN_ERROR; } if((plain =fopen(plainFile,“wb“))==NULL){ return PLAIN_FILE_OPEN_ERROR; }
//設置金鑰 memcpy(keyBlock,keyStr,8); //將金鑰轉換為二進位流 Char8ToBit64(keyBlock,bKey); //生成子金鑰 DES_MakeSubKeys(bKey,subKeys);
//取文件長度 fseek(cipher,0,SEEK_END); //將文件指針置尾 fileLen =ftell(cipher); //取文件指針當前位置 rewind(cipher); //將文件指標重指向文件頭 while(1){ //密文的位元組數一定��8的整數倍 fread(cipherBlock,sizeof(char),8,cipher); DES_DecryptBlock(cipherBlock,subKeys,plainBlock); times +=8; if(times < fileLen){ fwrite(plainBlock,sizeof(char),8,plain); } else{ break; } } //判斷末尾��否被填充 if(plainBlock[7]<8){ for(count =8– plainBlock[7]; count <7; count++){ if(plainBlock[count]!=‘\0’){ break; } } } if(count ==7){//有填充 fwrite(plainBlock,sizeof(char),8– plainBlock[7],plain); } else{//無填充 fwrite(plainBlock,sizeof(char),8,plain); }
fclose(plain); fclose(cipher); return OK; } intmain() { clock_t a,b; a =clock(); DES_Encrypt(“C:\\Users\\RD\\Desktop\\CB_C_DES.txt“,“CB_C_DES“,“C:\\Users\\RD\\Desktop\\CB_C_DES_e.txt“); b =clock(); printf(“加密消耗%d毫秒\n“,b–a);
system(“pause“); a =clock(); DES_Decrypt(“C:\\Users\\RD\\Desktop\\CB_C_DES_e.txt“,“CB_C_DES“,“C:\\Users\\RD\\Desktop\\CB_C_DES_d.txt“); b =clock(); printf(“解密消耗%d毫秒\n“,b–a); system(“pause“); return0; }
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