SHA1算法C语言实现

最新推荐文章于 2024-05-17 22:27:04 发布

dawnplunus

最新推荐文章于 2024-05-17 22:27:04 发布

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分类专栏：算法源码文章标签： sha1 算法 c语言源码

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本文详细介绍了如何实现SHA-1散列算法，包括参数解释、内部逻辑和关键步骤，帮助开发者理解并应用这一安全散列算法。

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使用说明：
将斜杠下面的源码复制到自己的源码中，在主函数之前加上函数声明，
之后便可在主函数中调用调用该函数了。
参数add是需要散列的数据的地址；
参数Length是需要散列的数据的长度（单位字节）；
参数add1是用来接受散列值的内存块的地址，该内存块的长度必须大于等于20字节；
//////////////////////////////////////////////////////////////////////////////////////
void sha1( void *add,unsigned long length,void *add1 )
{
unsigned char tempa;

unsigned long hash[5];

unsigned long long raw;

unsigned long a,b,c,d,e;

unsigned long buffer[20],temp;

unsigned long offset=0,offset1,offset2;

unsigned long count,count1,count2,count3=7;

hash[0]=a=0x67452301;

hash[1]=b=0xEFCDAB89;

hash[2]=c=0x98BADCFE;

hash[3]=d=0x10325476;

hash[4]=e=0xC3D2E1F0;

raw=length*8;

offset1=length;

offset2=length*8%512;

if(offset2>=0&&offset2<=447)

offset2=(512-offset2)/8;

else

offset2=(1024-offset2)/8;

count=(offset2+length)/64;

offset2=offset2+length-8;

   for(count1=1;count1<=count;count1++)
   {
      for(count2=0;count2<=63;count2++,offset++)
      {
         if(offset>=0&&offset<offset1)

{*((unsigned char *)buffer+count2)=*((unsigned char *)add+offset);}

else if (offset==offset1)

{*((unsigned char *)buffer+count2)=128;}

else if (offset>offset1&&offset<offset2)

{*((unsigned char *)buffer+count2)=0;}

         else if (offset>=offset2)
         {
            *((unsigned char *)buffer+count2)=*((unsigned char *)(&raw)+count3);

            count3--;
         }
         else
         {;}
      }
      for(count2=0;count2<=15;count2++)
      {
        tempa=*((unsigned char *)(&buffer[count2])+3);

*((unsigned char *)(&buffer[count2])+3)=*((unsigned char *)(&buffer[count2]));

*((unsigned char *)(&buffer[count2]))=tempa;

tempa=*((unsigned char *)(&buffer[count2])+2);

*((unsigned char *)(&buffer[count2])+2)=*((unsigned char *)(&buffer[count2])+1);

        *((unsigned char *)(&buffer[count2])+1)=tempa;
      }
      temp=buffer[13]^buffer[8]^buffer[2]^buffer[0];

buffer[16]=temp<<1|temp>>31;

temp=buffer[14]^buffer[9]^buffer[3]^buffer[1];

buffer[17]=temp<<1|temp>>31;

temp=buffer[15]^buffer[10]^buffer[4]^buffer[2];

buffer[18]=temp<<1|temp>>31;

temp=buffer[16]^buffer[11]^buffer[5]^buffer[3];

buffer[19]=temp<<1|temp>>31;

      for(count2=0;count2<=19;count2++)
      {
        temp=b&c|~b&d;

temp=(a<<5|a>>27)+temp+e+buffer[count2]+0x5A827999;

        e=d;d=c;c=b<<30|b>>2;b=a;a=temp;
      }
      for(count2=0;count2<=19;count2++)
      {
        temp=buffer[(17+count2)%20]^buffer[(12+count2)%20];

temp=temp^buffer[(6+count2)%20]^buffer[(4+count2)%20];

        buffer[count2]=temp<<1|temp>>31;
      }
      for(count2=0;count2<=19;count2++)
      {
        temp=b^c^d;

temp=(a<<5|a>>27)+temp+e+buffer[count2]+0x6ED9EBA1;

        e=d;d=c;c=b<<30|b>>2;b=a;a=temp;
      }
      for(count2=0;count2<=19;count2++)
      {
        temp=buffer[(17+count2)%20]^buffer[(12+count2)%20];

temp=temp^buffer[(6+count2)%20]^buffer[(4+count2)%20];

        buffer[count2]=temp<<1|temp>>31;
      }
      for(count2=0;count2<=19;count2++)
      {
        temp=b&c|b&d|c&d;

temp=(a<<5|a>>27)+temp+e+buffer[count2]+0x8F1BBCDC;

        e=d;d=c;c=b<<30|b>>2;b=a;a=temp;
      }
      for(count2=0;count2<=19;count2++)
      {
        temp=buffer[(17+count2)%20]^buffer[(12+count2)%20];

temp=temp^buffer[(6+count2)%20]^buffer[(4+count2)%20];

        buffer[count2]=temp<<1|temp>>31;
      }
      for(count2=0;count2<=19;count2++)
      {
        temp=b^c^d;

temp=(a<<5|a>>27)+temp+e+buffer[count2]+0xCA62C1D6;

        e=d;d=c;c=b<<30|b>>2;b=a;a=temp;
      }
    hash[0]=hash[0]+a;
    hash[1]=hash[1]+b;
    hash[2]=hash[2]+c;
    hash[3]=hash[3]+d;
    hash[4]=hash[4]+e;
    a=hash[0];b=hash[1];c=hash[2];d=hash[3];e=hash[4];
}
for(count2=0;count2<=4;count2++)
{
    tempa=*((unsigned char *)(&hash[count2])+3);

*((unsigned char *)(&hash[count2])+3)=*((unsigned char *)(&hash[count2]));

*((unsigned char *)(&hash[count2]))=tempa;

tempa=*((unsigned char *)(&hash[count2])+2);

*((unsigned char *)(&hash[count2])+2)=*((unsigned char *)(&hash[count2])+1);

*((unsigned char *)(&hash[count2])+1)=tempa;
}
*((unsigned long *)add1)=hash[0];
*((unsigned long *)add1+1)=hash[1];
*((unsigned long *)add1+2)=hash[2];
*((unsigned long *)add1+3)=hash[3];
*((unsigned long *)add1+4)=hash[4];

return;

}