rc5.cpp

根据rc5的c算法修改

/* RC5.c -- Reference implementation of RC5-32/12/16 in C.        */
/* Copyright (C) 1995 RSA Data Security, Inc.                        */

#include "rc5.h"
#include <string.h>

CRC5::CRC5()
{
}

void CRC5::ENCRYPT(LWORD *pt, LWORD *ct) 
/* Do Encrypt 2 WORD input pt/output ct*/
{ 
   LWORD i, A=pt[0]+S[0], B=pt[1]+S[1];
   for (i=1; i<=rn; i++) 
   { 
      A = ROTL(A^B,B)+S[2*i]; 
      B = ROTL(B^A,A)+S[2*i+1]; 
   }
   ct[0] = A; 
   ct[1] = B;  
} 

void CRC5::DECRYPT(LWORD *ct, LWORD *pt) 
/*Do Decrypt 2 WORD input ct/output pt    */
{ 
   LWORD i, B=ct[1], A=ct[0];
   for (i=rn; i>0; i--) 
   { 
      B = ROTR(B-S[2*i+1],A)^A; 
      A = ROTR(A-S[2*i],B)^B; 
   }
   pt[1] = B-S[1]; 
   pt[0] = A-S[0];  
} 

void CRC5::SETUP(unsigned char *K) /* secret input key K[0...b-1] */
{  
	LWORD P = 0xb7e15163;
	LWORD Q = 0x9e3779b9;  /* magic constants             */

    LWORD i, j, k, u=ws/8, A, B, L[cn]; 
    /* Initialize L, then S, then mix key into S */
    for (i=bn-1,L[cn-1]=0; i!=-1; i--) 
      L[i/u] = (L[i/u]<<8)+K[i];
    for (S[0]=P,i=1; i<ts; i++) 
      S[i] = S[i-1]+Q;
    for (A=B=i=j=k=0; k<3*ts; k++,i=(i+1)%ts,j=(j+1)%cn)   /* 3*t > 3*c */
    { 
      A = S[i] = ROTL(S[i]+(A+B),3);  
      B = L[j] = ROTL(L[j]+(A+B),(A+B)); 
    } 
} 


/*change the miwen stored in char to longch is type of unsigned char ,lg is type of unsigned long*/
unsigned char CRC5::CharToLong(unsigned char *ch,unsigned long *lg)
{
	int i;

	lg[0]=lg[1]=0L;
	for(i = 0;i<4;i++)
	{
		lg[0]=lg[0] | ch[i];
	    if (i != 3 )
			lg[0]=lg[0]<<8;
	}

		for(i = 4;i<8;i++)
	{
		lg[1]=lg[1] | ch[i];
	    if (i != 7 )
			lg[1]=lg[1]<<8;
	}
        return 0;

}

/*change the miwen stored in long to  charlg store unsigned long,ch store unsigned char */
unsigned char CRC5::LongToChar(unsigned long *lg,unsigned char *ch)
{
	unsigned long ltc[]={
			0xff000000,0x00ff0000,
			0x0000ff00,0x000000ff
	};

	int i;

	for(i = 0;i<4;i++)
	{
     ch[i]=(unsigned char)((lg[0] & ltc[i])>>(24-8*i));
	    
	}

		for(i = 4;i<8;i++)
	{
			ch[i]=(unsigned char)((lg[1] & ltc[i-4])>>(24-8*(i-4)));
	}
         return 0;

}

void CRC5::Setup(unsigned char *K)
{
   unsigned char key[16];
   int len;
   len = strlen((char *)K);
   if(len>16)
      len = 16;
   memset(key, 0, 16);
   memcpy(key, K, len);
   SETUP(key);
}

unsigned long CRC5::Encrypt(unsigned char * ibuf,unsigned char * obuf,unsigned long len)
{
   unsigned long lent,i,ilg[2],olg[2];
   /*lent:lenth of the char can encrypted 
   ilg:every 4 word of will encrypted char
     olg:every 4 word of encrypted char    
   */
   unsigned char * iptr=ibuf, *optr=obuf;
   lent=len&0xFFFFFFF8;                    /*let lent is times of 8 */
   
   for(i=0;i<lent/8;i++)                   /*every 8 bytes one time*/ 
   {
      ilg[0]=0L;
      ilg[1]=0L;
      olg[0]=0L;
      olg[1]=0L;
      CharToLong(iptr,ilg);
      ENCRYPT(ilg,olg);
      LongToChar(olg,optr);
      iptr+=8;
      optr+=8;
   }
   if(lent<len)                            /*copy the rest char*/
   {
      for(i=lent;i<len;i++)
      {
         *optr=*iptr;
         optr++;
         iptr++;
      }
   }
   
   return lent;
}

unsigned long CRC5::Decrypt(unsigned char * ibuf,unsigned char * obuf,unsigned long len)
{
   unsigned long i,lent,ilg[2],olg[2];
   /* lent:lenth of char will be decrypted
      ilg:every 4 word of will be decrypted
      olg:every 4 word of decrypted char
   */

   unsigned char * iptr=ibuf,* optr=obuf; 
   /*let lenth of char will be decrypted is times 8 */
   lent=len&0xFFFFFFF8;

   for (i=0;i<lent/8;i++)
   {
      ilg[0]=0L;
      ilg[1]=0L;
      olg[0]=0L;
      olg[1]=0L;
      CharToLong(iptr,ilg);
      DECRYPT(ilg,olg);
      LongToChar(olg,optr);
      iptr+=8;
      optr+=8;
   }
   if(lent<len)
   {
      for(i=lent;i<len;i++)
      {
         *optr=*iptr;
         iptr++;
         optr++;
      }
   }
   return lent;
}

CString CRC5::Decrypt(CString str)
{
	unsigned char key[16]={0x7, 0x0, 0x9, 0x1, 0x5, 0x70, 0x91, 0x5, 
		0x51, 0x90, 0x7, 0x5, 0x1, 0x9, 0x0, 0x7};
	Setup(key);

	int len=str.GetLength();
	char * bin;
	bin = PCHAR(malloc(len+1));
	memset(bin, 0, len+1);
	HexToBin(PCHAR(str.GetBuffer(len)), bin, len);
	
	len=len/2;
	UPCHAR obuf;
	obuf = byte*(malloc(len+1));
	memset(obuf, 0, len+1);
	Decrypt(UPCHAR(bin), obuf, len);

	return _T(obuf);
}

CString CRC5::Encrypt(CString str)
{
	unsigned char key[16]={0x7, 0x0, 0x9, 0x1, 0x5, 0x70, 0x91, 0x5, 
		0x51, 0x90, 0x7, 0x5, 0x1, 0x9, 0x0, 0x7};
	Setup(key);
	
	int len=str.GetLength();
	if(len<8)
		len=len+8;                         //str.GetBuffer(len)
	UPCHAR obuf;
	obuf = UPCHAR(malloc(len+1));
	memset(obuf, 0, len+1);
	Encrypt(UPCHAR(str.GetBuffer(len)), obuf, len);

	char * hex;
	hex = PCHAR(malloc(2*len+1));
	memset(hex, 0, 2*len+1);
	BinToHex(PCHAR(obuf), hex, len);
	return _T(hex);
}

void CRC5::BinToHex(LPSTR buf, LPSTR hex, int bufSize)
{
	int i;
	unsigned char c, j, k;
	LPSTR ptrBuf=buf;
	LPSTR ptrHex=hex;
	for(i=0; i<bufSize; i++)
	{
		c=*ptrBuf;
		j=c/16;
		k=c-j*16;
		*ptrHex=j>9 ? 'A'+j-10 : '0'+j;
		ptrHex++;
		*ptrHex=k>9 ? 'A'+k-10 : '0'+k;
		ptrHex++;
		ptrBuf++;
	}
}

void CRC5::HexToBin(LPSTR hex, LPSTR buf, int bufSize)
{
	int i;
	unsigned char c, j, k;
	LPSTR ptrBuf=buf;
	LPSTR ptrHex=hex;
	for(i=0; i<bufSize; i++)
	{
		j=*ptrHex;
		j=((j>='A')&&(j<='F')) ? j-'A'+10 : j-'0';
		ptrHex++;
		k=*ptrHex;
		k=((k>='A')&&(k<='F')) ? k-'A'+10 : k-'0';
		c=j*16+k;
		*ptrBuf=c;
		ptrHex++;
		ptrBuf++;
	}
}