DES加密算法C语言实现
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DES加密算法C实现mac.c#include #include
/** 程序描述: 加/解密公用函数* decrypt / encrypt routine**/
#define u_char unsigned char
void FDES(u_char *key,u_char *text,u_char *mtext);void _FDES(u_char *key,u_char *mtext,u_char *text);void Fencrypt0(u_char *text,u_char *mtext);void Fdiscrypt0(u_char *mtext,u_char *text);void Fexpand0(u_char *in,u_char *out);void Fcompress0(u_char *out,u_char *in);void Fcompress016(u_char *out,u_char *in);void Fsetkeystar(u_char bits[64]);void FLS(u_char *bits,u_char *buffer,int count);void Fson(u_char *cc,u_char *dd,u_char *kk);void Fiip(u_char *text,u_char *ll,u_char *rr);void _Fiip(u_char *text,u_char *ll,u_char *rr);void FF(int n,u_char *ll,u_char *rr,u_char *LL,u_char *RR);void Fs_box(u_char *aa,u_char *bb);
u_char C[17][28],D[17][28],K[17][48];
/****************************************************************************** function: DES* parameter: u_char * key ; key for encrypt* u_char * text ; plain text * u_char * mtext ; encipher result* return: none*****************************************************************************/void FDES(u_char *key,u_char *text,u_char *mtext){ u_char tmp[64]; Fexpand0(key,tmp); Fsetkeystar(tmp); Fencrypt0(text,mtext);}
/****************************************************************************** function: DES* parameter: u_char * key ; key for encrypt* u_char * mtext ; encipher data * u_char * text ; plain data* return: none*****************************************************************************/void _FDES(u_char *key,u_char *mtext,u_char *text){ u_char tmp[64]; Fexpand0(key,tmp); Fsetkeystar(tmp); Fdiscrypt0(mtext,text);}
void Fencrypt0(u_char *text,u_char *mtext){ u_char ll[64],rr[64],LL[64],RR[64]; u_char tmp[64]; int i,j; Fiip(text,ll,rr);
for (i=1;i<17;i++) { FF(i,ll,rr,LL,RR); for (j=0;j<32;j++) { ll[j]=LL[j]; rr[j]=RR[j]; } }
_Fiip(tmp,rr,ll);
Fcompress0(tmp,mtext);}
void Fdiscrypt0(u_char *mtext,u_char *text){ u_char ll[64],rr[64],LL[64],RR[64]; u_char tmp[64]; int i,j; Fiip(mtext,ll,rr);
for (i=16;i>0;i--) { FF(i,ll,rr,LL,RR); for (j=0;j<32;j++) { ll[j]=LL[j]; rr[j]=RR[j]; } }
_Fiip(tmp,rr,ll);
Fcompress0(tmp,text);}
void Fexpand0(u_char *in,u_char *out){ int divide; int i,j;
for (i=0;i<8;i++) { divide=0x80; for (j=0;j<8;j++) { *out++=(in/divide)&1; divide/=2; } }}
void Fcompress0(u_char *out,u_char *in){ int times; int i,j;
for (i=0;i<8;i++) { times=0x80; in=0; for (j=0;j<8;j++) { in+=(*out++)*times; times/=2; } }}void Fcompress016(u_char *out,u_char *in){ int times; int i,j;
for (i=0;i<16;i++) { times=0x8; in='0'; for (j=0;j<4;j++) { in+=(*out++)*times; times/=2; } }}
int pc_1_cp[28]={ 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};int pc_1_dp[28]={ 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};int pc_2p[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};
int ls_countp[16]={ 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};
void Fsetkeystar(u_char bits[64]){ int i,j;
for (i=0;i<28;i++) C[0]=bits[pc_1_cp-1]; for (i=0;i<28;i++) D[0]=bits[pc_1_dp-1]; for (j=0;j<16;j++) { FLS(C[j],C[j+1],ls_countp[j]); FLS(D[j],D[j+1],ls_countp[j]); Fson(C[j+1],D[j+1],K[j+1]); }}
void FLS(u_char *bits,u_char *buffer,int count){ int i,j; for (i=0;i<28;i++) { buffer=bits[(i+count)%28]; }}
void Fson(u_char *cc,u_char *dd,u_char *kk){ int i,j; u_char buffer[56]; for (i=0;i<28;i++) buffer=*cc++;
for (i=28;i<56;i++) buffer=*dd++;
for (i=0;i<48;i++) *kk++=buffer[pc_2p-1];}
int iip_tab_p[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};int _iip_tab_p[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};
void Fiip(u_char *text,u_char *ll,u_char *rr){ int i,j; u_char buffer[64]; u_char tmp[64]; Fexpand0(text,buffer);
for (i=0;i<32;i++) ll=buffer[iip_tab_p-1];
for (i=0;i<32;i++) rr=buffer[iip_tab_p[i+32]-1];}
void _Fiip(u_char *text,u_char *ll,u_char *rr){ int i,j; u_char tmp[64]; for (i=0;i<32;i++) tmp=ll; for (i=32;i<64;i++) tmp=rr[i-32]; for (i=0;i<64;i++) text=tmp[_iip_tab_p-1];}
int e_r_p[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};
int local_PP[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};int ccom_SSS_p[8][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,/* err on */ 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,
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,
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,
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, /* err on */
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, /* err on */ 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,
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,
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,
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 FF(int n,u_char *ll,u_char *rr,u_char *LL,u_char *RR){ int i,j; u_char buffer[64],tmp[64]; for (i=0;i<48;i++) buffer=rr[e_r_p-1]; for (i=0;i<48;i++) buffer=(buffer+K[n])&1;
Fs_box(buffer,tmp);
for (i=0;i<32;i++) buffer=tmp[local_PP-1];
for (i=0;i<32;i++) RR=(buffer+ll)&1;
for (i=0;i<32;i++) LL=rr;
}
void Fs_box(u_char *aa,u_char *bb){ int i,j,k,m; int y,z; u_char ss[8]; m=0; for (i=0;i<8;i++) { j=6*i; y=aa[j]*2+aa[j+5]; z=aa[j+1]*8+aa[j+2]*4+aa[j+3]*2+aa[j+4]; ss=ccom_SSS_p[y][z]; y=0x08; for (k=0;k<4;k++) { bb[m++]=(ss/y)&1; y/=2; }
}}
