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DES加密与解密（c语言版)
其实是作业啦，写这个东西花了我不少时间，明天就是deadline了，熬夜至凌晨写完的，放在这里做个纪念，代码遵循GPL协议,可随意下载，修改，共享。
文中有许多注释掉的东西，是测试的时候用的。
#include <string.h> #include <stdio.h> class DES { public: ~DES() {} void setkey(const unsigned char *); void enctransform(const unsigned char *,unsigned char *); void dectransform(const unsigned char *,unsigned char *); private: bool enckey[16][48];//存放加密子密钥 bool deckey[16][48];//存放解密子密钥 // initial permutation IP const static unsigned char IP_Table[64]; // final permutation IP^-1 const static unsigned char IPR_Table[64]; // expansion operation matrix const static unsigned char E_Table[48]; // 32-bit permutation function P used on the output of the S-boxes const static unsigned char P_Table[32]; // permuted choice table (key) const static unsigned char PC1_Table[56]; // permuted choice key (table) const static unsigned char PC2_Table[48]; // number left rotations of pc1 const static unsigned char LOOP_Table[16]; // The S-boxes const static unsigned char S_Box[8][4][16]; //加入其他私有成员函数 }; const unsigned char DES::IP_Table[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 }; // final permutation IP^-1 const unsigned char DES::IPR_Table[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 }; // expansion operation matrix const unsigned char DES::E_Table[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 }; // 32-bit permutation function P used on the output of the S-boxes const unsigned char DES::P_Table[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 }; // permuted choice table (key) const unsigned char DES::PC1_Table[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 }; // permuted choice key (table) const unsigned char DES::PC2_Table[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 }; // number left rotations of pc1 const unsigned char DES::LOOP_Table[16] = { 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1 }; // The S-boxes const unsigned char DES::S_Box[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 }; void DES::setkey( unsigned char const *userkey/*用户输入的64位密钥首地址*/ ) { //密钥扩展算法，即由主密钥生成子密钥，参见教材44-45页 unsigned char userkey2[8]; for(int ii=0;ii<8;ii++) userkey2[ii]=userkey[ii];//复制主密钥 //化比特为数组 unsigned char key[64]; for(int i=7;i>=0;i--) for(int j=7;j>=0;j--) { key[i*8+j]=userkey2[i]&0x01; userkey2[i]=userkey2[i]>>1; } //输出测试 // for(int jj=0;jj<64;jj++) // printf("%d",key[jj]); //去除校验位，变为56 unsigned char key2[56]; for(int k=1,kk=0;k<=64;k++) { if(k%8!=0) { key2[kk]=key[k-1]; kk++; } } //输出测试 去除校验位后的 //printf("\n"); //for(int j=0;j<56;j++) // printf("%d",key2[j]); // printf("\n"); unsigned char c0[28]; unsigned char c1[28]; //拆分为两个 for(int p=0;p<28;p++) { c0[p]=key2[PC1_Table[p]-1]; c1[p]=key2[PC1_Table[p+28]-1];//c1就是d } //输出测试两个拆分 //for(int p=0;p<28;p++) //{ // printf("%d",c0[p]); //} //printf("\n"); // for(int p=0;p<28;p++) //{ // printf("%d",c1[p]); //} // printf("\n"); int tempint1; int tempint2; int tempint11; int tempint22; //16个子密钥的生成 for(int i=0;i<16;i++) { if(LOOP_Table[i]==1) { tempint1=c0[0]; tempint11=c1[0]; for(int j=1;j<28;j++) { c0[j-1]=c0[j]; c1[j-1]=c1[j]; } c0[27]=tempint1; c1[27]=tempint11; } else { tempint1=c0[0]; tempint2=c0[1]; tempint11=c1[0]; tempint22=c1[1]; for(int j=2;j<28;j++) { c0[j-2]=c0[j]; c1[j-2]=c1[j]; } c0[26]=tempint1; c0[27]=tempint2; c1[26]=tempint11; c1[27]=tempint22; } for(int r=0;r<56;r++) { if(r<28) key2[r]=c0[r]; else key2[r]=c1[r-28]; } for(int r=0;r<48;r++) { enckey[i][r]=key2[PC2_Table[r]-1]; } // for(int k=0;k<48;k++) // printf("%d",enckey[i][k]); // printf("\n"); } //printf("\n"); } void DES::enctransform( const unsigned char *In /*待加密的64位数据首地址*/,unsigned char *Out ) { //加密变换算法，参见教材42、43、46页 unsigned char In2[8]; for(int ii=0;ii<8;ii++) In2[ii]=In[ii];//复制64位明文 //化比特为数组 unsigned char In3[64]; for(int i=7;i>=0;i--) for(int j=7;j>=0;j--) { In3[i*8+j]=In2[i]&0x01; In2[i]=In2[i]>>1; } //观察是否拆分成功 //到这里是对的 //for(int i=0;i<64;i++) // printf("%d",In3[i]); //printf("\n"); //printf("%d\n",In3[63]); //初始置换IP //到这里还是对的 unsigned char In4[64]; for(int i=0;i<64; i++) In4[i]=In3[IP_Table[i]-1]; //观察是否置换成功 //for(int i=0;i<64;i++) //printf("%d",In4[i]); //printf("\n"); //16次迭代 unsigned char L[32],R[32],tempL[32],tempR[32],F[32],FP[32],ER[48]; unsigned char B1[6],B2[6],B3[6],B4[6],B5[6],B6[6],B7[6],B8[6]; for(int i=0;i<32;i++) { L[i]=In4[i]; R[i]=In4[i+32]; } for(int i=0;i<16;i++) { for(int j=0;j<32;j++) { tempL[j]=L[j]; tempR[j]=R[j]; } for(int j=0;j<32;j++) L[j]=tempR[j]; //f函数定义 // for(int i3=0;i3<48;i3++) // printf("%d-",tempR[E_Table[i3]-1]); // printf("\n"); for(int i1=0;i1<48;i1++) ER[i1]=tempR[E_Table[i1]-1]^enckey[i][i1]; // for(int i2=0;i2<48;i2++) // printf("%d ",ER[i2]); // printf("\n"); for(int p=0;p<48;p++) { int temp=p/6; switch(temp) { case 0: B1[p]=ER[p];break; case 1: B2[p-6]=ER[p];break; case 2: B3[p-12]=ER[p];break; case 3: B4[p-18]=ER[p];break; case 4: B5[p-24]=ER[p];break; case 5: B6[p-30]=ER[p];break; case 6: B7[p-36]=ER[p];break; case 7: B8[p-42]=ER[p];break; default: printf("error in switch!\n"); } } unsigned char f; f=S_Box[0][B1[0]*2+B1[5]][B1[1]*8+B1[2]*4+B1[3]*2+B1[4]]; for(int f1=3;f1>=0;f1--) { F[f1]=f&0x01; f=f>>1; // printf("%d,%d:%d\n",f,f1,F[f1]); } f=S_Box[1][B2[0]*2+B2[5]][B2[1]*8+B2[2]*4+B2[3]*2+B2[4]]; for(int f1=3;f1>=0;f1--) { F[f1+4]=f&0x01; f=f>>1; } f=S_Box[2][B3[0]*2+B3[5]][B3[1]*8+B3[2]*4+B3[3]*2+B3[4]]; for(int f1=3;f1>=0;f1--) { F[f1+8]=f&0x01; f=f>>1; } f=S_Box[3][B4[0]*2+B4[5]][B4[1]*8+B4[2]*4+B4[3]*2+B4[4]]; for(int f1=3;f1>=0;f1--) { F[f1+12]=f&0x01; f=f>>1; } f=S_Box[4][B5[0]*2+B5[5]][B5[1]*8+B5[2]*4+B5[3]*2+B5[4]]; for(int f1=3;f1>=0;f1--) { F[f1+16]=f&0x01; f=f>>1; } f=S_Box[5][B6[0]*2+B6[5]][B6[1]*8+B6[2]*4+B6[3]*2+B6[4]]; for(int f1=3;f1>=0;f1--) { F[f1+20]=f&0x01; f=f>>1; } f=S_Box[6][B7[0]*2+B7[5]][B7[1]*8+B7[2]*4+B7[3]*2+B7[4]]; for(int f1=3;f1>=0;f1--) { F[f1+24]=f&0x01; f=f>>1; } f=S_Box[7][B8[0]*2+B8[5]][B8[1]*8+B8[2]*4+B8[3]*2+B8[4]]; for(int f1=3;f1>=0;f1--) { F[f1+28]=f&0x01; f=f>>1; } for(int q=0;q<32;q++) { FP[q]=F[P_Table[q]-1]; } for(int k=0;k<32;k++) { R[k]=tempL[k]^FP[k]; } } //合并 for(int i=0;i<32;i++) { In4[i]=R[i]; In4[i+32]=L[i]; } //逆置换 for(int i=0;i<64;i++) { In3[i]=In4[IPR_Table[i]-1]; } //ce shi // for(int i=0;i<64;i++) // printf("%d",In3[i]); //转出 1 2 4 8 16 32 64 128 for(int i=0;i<8;i++) { Out[i]=0; for(int j=0;j<8;j++) { int p=128,jj=j; while(jj!=0) { p=p/2; jj--; } Out[i]+=In3[i*8+j]*p; } } } void DES::dectransform( const unsigned char *In /*待解密的64位数据首地址*/, unsigned char *Out) { //解密变换算法，参见教材48页 unsigned char In2[8]; for(int ii=0;ii<8;ii++) In2[ii]=In[ii];//复制64位明文 //化比特为数组 unsigned char In3[64]; for(int i=7;i>=0;i--) for(int j=7;j>=0;j--) { In3[i*8+j]=In2[i]&0x01; In2[i]=In2[i]>>1; } //观察是否拆分成功 //到这里是对的 //for(int i=0;i<64;i++) // printf("%d",In3[i]); //printf("\n"); //printf("%d\n",In3[63]); //初始置换IP //到这里还是对的 unsigned char In4[64]; for(int i=0;i<64; i++) In4[i]=In3[IP_Table[i]-1]; //观察是否置换成功 //for(int i=0;i<64;i++) //printf("%d",In4[i]); //printf("\n"); //16次迭代 unsigned char L[32],R[32],tempL[32],tempR[32],F[32],FP[32],ER[48]; unsigned char B1[6],B2[6],B3[6],B4[6],B5[6],B6[6],B7[6],B8[6]; for(int i=0;i<32;i++) { L[i]=In4[i]; R[i]=In4[i+32]; } for(int i=0;i<16;i++) { for(int j=0;j<32;j++) { tempL[j]=L[j]; tempR[j]=R[j]; } for(int j=0;j<32;j++) L[j]=tempR[j]; //f函数定义 // for(int i3=0;i3<48;i3++) // printf("%d-",tempR[E_Table[i3]-1]); // printf("\n"); for(int i1=0;i1<48;i1++) ER[i1]=tempR[E_Table[i1]-1]^enckey[15-i][i1]; // for(int i2=0;i2<48;i2++) // printf("%d ",ER[i2]); // printf("\n"); for(int p=0;p<48;p++) { int temp=p/6; switch(temp) { case 0: B1[p]=ER[p];break; case 1: B2[p-6]=ER[p];break; case 2: B3[p-12]=ER[p];break; case 3: B4[p-18]=ER[p];break; case 4: B5[p-24]=ER[p];break; case 5: B6[p-30]=ER[p];break; case 6: B7[p-36]=ER[p];break; case 7: B8[p-42]=ER[p];break; default: printf("error in switch!\n"); } } unsigned char f; f=S_Box[0][B1[0]*2+B1[5]][B1[1]*8+B1[2]*4+B1[3]*2+B1[4]]; for(int f1=3;f1>=0;f1--) { F[f1]=f&0x01; f=f>>1; // printf("%d,%d:%d\n",f,f1,F[f1]); } f=S_Box[1][B2[0]*2+B2[5]][B2[1]*8+B2[2]*4+B2[3]*2+B2[4]]; for(int f1=3;f1>=0;f1--) { F[f1+4]=f&0x01; f=f>>1; } f=S_Box[2][B3[0]*2+B3[5]][B3[1]*8+B3[2]*4+B3[3]*2+B3[4]]; for(int f1=3;f1>=0;f1--) { F[f1+8]=f&0x01; f=f>>1; } f=S_Box[3][B4[0]*2+B4[5]][B4[1]*8+B4[2]*4+B4[3]*2+B4[4]]; for(int f1=3;f1>=0;f1--) { F[f1+12]=f&0x01; f=f>>1; } f=S_Box[4][B5[0]*2+B5[5]][B5[1]*8+B5[2]*4+B5[3]*2+B5[4]]; for(int f1=3;f1>=0;f1--) { F[f1+16]=f&0x01; f=f>>1; } f=S_Box[5][B6[0]*2+B6[5]][B6[1]*8+B6[2]*4+B6[3]*2+B6[4]]; for(int f1=3;f1>=0;f1--) { F[f1+20]=f&0x01; f=f>>1; } f=S_Box[6][B7[0]*2+B7[5]][B7[1]*8+B7[2]*4+B7[3]*2+B7[4]]; for(int f1=3;f1>=0;f1--) { F[f1+24]=f&0x01; f=f>>1; } f=S_Box[7][B8[0]*2+B8[5]][B8[1]*8+B8[2]*4+B8[3]*2+B8[4]]; for(int f1=3;f1>=0;f1--) { F[f1+28]=f&0x01; f=f>>1; } for(int q=0;q<32;q++) { FP[q]=F[P_Table[q]-1]; } for(int k=0;k<32;k++) { R[k]=tempL[k]^FP[k]; } } //合并 for(int i=0;i<32;i++) { In4[i]=R[i]; In4[i+32]=L[i]; } //逆置换 for(int i=0;i<64;i++) { In3[i]=In4[IPR_Table[i]-1]; } //ce shi // for(int i=0;i<64;i++) // printf("%d",In3[i]); //转出 1 2 4 8 16 32 64 128 for(int i=0;i<8;i++) { Out[i]=0; for(int j=0;j<8;j++) { int p=128,jj=j; while(jj!=0) { p=p/2; jj--; } Out[i]+=In3[i*8+j]*p; } } } int main() { unsigned int buf[8]; char choice=‘ ‘; char buffer[17]; unsigned char key[9], plaintext[9],ciphertext[9]; DES mydes; int ii; while(true) { do { printf("Please make a choice:\n 1.encryption\n 2.decryption\n 3.exit\n"); scanf("\n%c",&choice); }while(choice!=‘1‘&&choice!=‘2‘&&choice!=‘3‘); switch(choice) { case ‘1‘: printf("Please input key(length=16):\n****************\n"); scanf("%s",buffer); sscanf(buffer,"%2x%2x%2x%2x%2x%2x%2x%2x",&buf[0],&buf[1],&buf[2],&buf[3],&buf[4],&buf[5],&buf[6],&buf[7]); for(ii=0;ii<8;ii++) key[ii]=buf[ii]; printf("Please input plaintext(length=16):\n"); scanf("%s",buffer); sscanf(buffer,"%2x%2x%2x%2x%2x%2x%2x%2x",&buf[0],&buf[1],&buf[2],&buf[3],&buf[4],&buf[5],&buf[6],&buf[7]); for(ii=0;ii<8;ii++) plaintext[ii]=buf[ii]; mydes.setkey(key); mydes.enctransform(plaintext,ciphertext); for(ii=0;ii<8;ii++) buf[ii]=ciphertext[ii]; printf("ciphertext:\n%02x%02x%02x%02x%02x%02x%02x%02x\n",buf[0],buf[1],buf[2],buf[3],buf[4],buf[5],buf[6],buf[7]); break; case ‘2‘: printf("Please input key(length=16):\n****************\n"); scanf("%s",buffer); sscanf(buffer,"%2x%2x%2x%2x%2x%2x%2x%2x",&buf[0],&buf[1],&buf[2],&buf[3],&buf[4],&buf[5],&buf[6],&buf[7]); for(ii=0;ii<8;ii++) key[ii]=buf[ii]; printf("Please input ciphertext(length=16):\n"); scanf("%s",buffer); sscanf(buffer,"%2x%2x%2x%2x%2x%2x%2x%2x",&buf[0],&buf[1],&buf[2],&buf[3],&buf[4],&buf[5],&buf[6],&buf[7]); for(ii=0;ii<8;ii++) ciphertext[ii]=buf[ii]; mydes.setkey(key); mydes.dectransform(ciphertext,plaintext); for(ii=0;ii<8;ii++) buf[ii]=plaintext[ii]; printf("plaintext:\n%02x%02x%02x%02x%02x%02x%02x%02x\n",buf[0],buf[1],buf[2],buf[3],buf[4],buf[5],buf[6],buf[7]); break; case ‘3‘: return 0; break; } }//end of while(true) }
最终的效果：
DES加密与解密（c语言版)
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