DES加密算法C语言实现
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 <stdio.h>
#include <string.h>
/*
* 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;
}
}
}