跨平台C++ 对称加密解密函数

(2005-05-26 11:31:40)

void Encrypt(unsigned char* pdata,int len,unsigned longkey0,unsigned long key1)
{
union sDWORD
{
unsigned long ldata;
unsigned char b[4];
};

union sWORD
{
  short a;
  struct
  {
  unsigned char b0;
  unsigned char b1;
  }b;
};

union DISPLAY
{
  struct{ unsigned charv; }B;
  struct {
   unsigned charb0 :1; unsigned charb1 :1; unsigned charb2 :1; unsigned charb3 :1; unsigned charb4 :1; unsigned charb5 :1; unsigned charb6 :1; unsigned charb7 :1;
  }b;
};

unsigned char *ps=pdata;
int ByteLengthBak=len;
union sDWORD p;
union sDWORD k;
DISPLAY c;
p.ldata=key1;
k.ldata=key0;
char buffer1,buffer2;
unsigned char RBKEY=p.b[0];
unsigned char RBKEY1=p.b[3];
unsigned char RBKEY2=p.b[1];
unsigned char RBKEY3=p.b[2];
RBKEY^=key0;

buffer1=p.b[1];
p.b[1]=k.b[3];
buffer2=p.b[3];
p.b[3]=k.b[1];
k.b[1]=buffer1;
k.b[3]=buffer2;

int count=0;
while(len)
{
  if (count==8) count=0;
  if(count<4)
  {
*(pdata++)^=k.b[count];
  }
  else
  {
*(pdata++)^=p.b[count-4];
  }
  count++;
  len--;
}
for(int ii=0;ii<ByteLengthBak;ii++)
{
  ps[ii]=ps[ii]^(RBKEY);
  c.B.v=ps[ii];
  c.b.b0^=(RBKEY1&0x1);
  c.b.b2^=((RBKEY1&0x2)>>1);
  c.b.b4^=((RBKEY1&0x4)>>2);
  c.b.b6^=((RBKEY1&0x8)>>3);
  c.b.b7^=((RBKEY1&0x80)>>7);
  c.b.b1^=c.b.b3;
  c.b.b3^=c.b.b5;
  c.b.b5^=c.b.b7;

  c.b.b5^=p.b[0];
  c.b.b3^=p.b[1];
  c.b.b1^=p.b[2];
  c.b.b7^=p.b[3];

  c.b.b0^=(RBKEY2&0x1);
  c.b.b2^=((RBKEY3&0x4)>>1);
  c.b.b4^=((RBKEY2&0x8)>>3);
  c.b.b6^=((RBKEY3&0x80)>>7);
}
}

void Encrypt(unsigned char* pdata,int len,string key)
{
CMD5 md5;
md5.GenerateMD5 ((unsigned char*)key.c_str (),key.length());
Encrypt(pdata,len,md5.m_data[0]^md5.m_data[3],md5.m_data[1]^md5.m_data[2]);
}

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