毕业论文论文范文课程设计实践报告法律论文英语论文教学论文医学论文农学论文艺术论文行政论文管理论文计算机安全
您现在的位置: 毕业论文 >> 报告 >> 正文

DES加密算法C语言实现

更新时间:2007-11-12:  来源:毕业论文

DES加密算法C语言实现

更多更新更免费论文网,专业毕业设计论文,课程设计源代码,上机实习报告,实验报告请点击www.751com.cn

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;
           }

     }
}

DES加密算法C语言实现下载如图片无法显示或论文不完整,请联系qq752018766
设为首页 | 联系站长 | 友情链接 | 网站地图 |

copyright©751com.cn 辣文论文网 严禁转载
如果本毕业论文网损害了您的利益或者侵犯了您的权利,请及时联系,我们一定会及时改正。