d3des.c

des加解密实现

	0x80000020L, 0x80108020L, 0x80108000L, 0x80000000L,
	0x80008000L, 0x00100000L, 0x00000020L, 0x80100020L,
	0x00108000L, 0x00100020L, 0x80008020L, 0x00000000L,
	0x80000000L, 0x00008000L, 0x00108020L, 0x80100000L,
	0x00100020L, 0x80000020L, 0x00000000L, 0x00108000L,
	0x00008020L, 0x80108000L, 0x80100000L, 0x00008020L,
	0x00000000L, 0x00108020L, 0x80100020L, 0x00100000L,
	0x80008020L, 0x80100000L, 0x80108000L, 0x00008000L,
	0x80100000L, 0x80008000L, 0x00000020L, 0x80108020L,
	0x00108020L, 0x00000020L, 0x00008000L, 0x80000000L,
	0x00008020L, 0x80108000L, 0x00100000L, 0x80000020L,
	0x00100020L, 0x80008020L, 0x80000020L, 0x00100020L,
	0x00108000L, 0x00000000L, 0x80008000L, 0x00008020L,
	0x80000000L, 0x80100020L, 0x80108020L, 0x00108000L };

static unsigned long SP3[64] = {
	0x00000208L, 0x08020200L, 0x00000000L, 0x08020008L,
	0x08000200L, 0x00000000L, 0x00020208L, 0x08000200L,
	0x00020008L, 0x08000008L, 0x08000008L, 0x00020000L,
	0x08020208L, 0x00020008L, 0x08020000L, 0x00000208L,
	0x08000000L, 0x00000008L, 0x08020200L, 0x00000200L,
	0x00020200L, 0x08020000L, 0x08020008L, 0x00020208L,
	0x08000208L, 0x00020200L, 0x00020000L, 0x08000208L,
	0x00000008L, 0x08020208L, 0x00000200L, 0x08000000L,
	0x08020200L, 0x08000000L, 0x00020008L, 0x00000208L,
	0x00020000L, 0x08020200L, 0x08000200L, 0x00000000L,
	0x00000200L, 0x00020008L, 0x08020208L, 0x08000200L,
	0x08000008L, 0x00000200L, 0x00000000L, 0x08020008L,
	0x08000208L, 0x00020000L, 0x08000000L, 0x08020208L,
	0x00000008L, 0x00020208L, 0x00020200L, 0x08000008L,
	0x08020000L, 0x08000208L, 0x00000208L, 0x08020000L,
	0x00020208L, 0x00000008L, 0x08020008L, 0x00020200L };

static unsigned long SP4[64] = {
	0x00802001L, 0x00002081L, 0x00002081L, 0x00000080L,
	0x00802080L, 0x00800081L, 0x00800001L, 0x00002001L,
	0x00000000L, 0x00802000L, 0x00802000L, 0x00802081L,
	0x00000081L, 0x00000000L, 0x00800080L, 0x00800001L,
	0x00000001L, 0x00002000L, 0x00800000L, 0x00802001L,
	0x00000080L, 0x00800000L, 0x00002001L, 0x00002080L,
	0x00800081L, 0x00000001L, 0x00002080L, 0x00800080L,
	0x00002000L, 0x00802080L, 0x00802081L, 0x00000081L,
	0x00800080L, 0x00800001L, 0x00802000L, 0x00802081L,
	0x00000081L, 0x00000000L, 0x00000000L, 0x00802000L,
	0x00002080L, 0x00800080L, 0x00800081L, 0x00000001L,
	0x00802001L, 0x00002081L, 0x00002081L, 0x00000080L,
	0x00802081L, 0x00000081L, 0x00000001L, 0x00002000L,
	0x00800001L, 0x00002001L, 0x00802080L, 0x00800081L,
	0x00002001L, 0x00002080L, 0x00800000L, 0x00802001L,
	0x00000080L, 0x00800000L, 0x00002000L, 0x00802080L };

static unsigned long SP5[64] = {
	0x00000100L, 0x02080100L, 0x02080000L, 0x42000100L,
	0x00080000L, 0x00000100L, 0x40000000L, 0x02080000L,
	0x40080100L, 0x00080000L, 0x02000100L, 0x40080100L,
	0x42000100L, 0x42080000L, 0x00080100L, 0x40000000L,
	0x02000000L, 0x40080000L, 0x40080000L, 0x00000000L,
	0x40000100L, 0x42080100L, 0x42080100L, 0x02000100L,
	0x42080000L, 0x40000100L, 0x00000000L, 0x42000000L,
	0x02080100L, 0x02000000L, 0x42000000L, 0x00080100L,
	0x00080000L, 0x42000100L, 0x00000100L, 0x02000000L,
	0x40000000L, 0x02080000L, 0x42000100L, 0x40080100L,
	0x02000100L, 0x40000000L, 0x42080000L, 0x02080100L,
	0x40080100L, 0x00000100L, 0x02000000L, 0x42080000L,
	0x42080100L, 0x00080100L, 0x42000000L, 0x42080100L,
	0x02080000L, 0x00000000L, 0x40080000L, 0x42000000L,
	0x00080100L, 0x02000100L, 0x40000100L, 0x00080000L,
	0x00000000L, 0x40080000L, 0x02080100L, 0x40000100L };

static unsigned long SP6[64] = {
	0x20000010L, 0x20400000L, 0x00004000L, 0x20404010L,
	0x20400000L, 0x00000010L, 0x20404010L, 0x00400000L,
	0x20004000L, 0x00404010L, 0x00400000L, 0x20000010L,
	0x00400010L, 0x20004000L, 0x20000000L, 0x00004010L,
	0x00000000L, 0x00400010L, 0x20004010L, 0x00004000L,
	0x00404000L, 0x20004010L, 0x00000010L, 0x20400010L,
	0x20400010L, 0x00000000L, 0x00404010L, 0x20404000L,
	0x00004010L, 0x00404000L, 0x20404000L, 0x20000000L,
	0x20004000L, 0x00000010L, 0x20400010L, 0x00404000L,
	0x20404010L, 0x00400000L, 0x00004010L, 0x20000010L,
	0x00400000L, 0x20004000L, 0x20000000L, 0x00004010L,
	0x20000010L, 0x20404010L, 0x00404000L, 0x20400000L,
	0x00404010L, 0x20404000L, 0x00000000L, 0x20400010L,
	0x00000010L, 0x00004000L, 0x20400000L, 0x00404010L,
	0x00004000L, 0x00400010L, 0x20004010L, 0x00000000L,
	0x20404000L, 0x20000000L, 0x00400010L, 0x20004010L };

static unsigned long SP7[64] = {
	0x00200000L, 0x04200002L, 0x04000802L, 0x00000000L,
	0x00000800L, 0x04000802L, 0x00200802L, 0x04200800L,
	0x04200802L, 0x00200000L, 0x00000000L, 0x04000002L,
	0x00000002L, 0x04000000L, 0x04200002L, 0x00000802L,
	0x04000800L, 0x00200802L, 0x00200002L, 0x04000800L,
	0x04000002L, 0x04200000L, 0x04200800L, 0x00200002L,
	0x04200000L, 0x00000800L, 0x00000802L, 0x04200802L,
	0x00200800L, 0x00000002L, 0x04000000L, 0x00200800L,
	0x04000000L, 0x00200800L, 0x00200000L, 0x04000802L,
	0x04000802L, 0x04200002L, 0x04200002L, 0x00000002L,
	0x00200002L, 0x04000000L, 0x04000800L, 0x00200000L,
	0x04200800L, 0x00000802L, 0x00200802L, 0x04200800L,
	0x00000802L, 0x04000002L, 0x04200802L, 0x04200000L,
	0x00200800L, 0x00000000L, 0x00000002L, 0x04200802L,
	0x00000000L, 0x00200802L, 0x04200000L, 0x00000800L,
	0x04000002L, 0x04000800L, 0x00000800L, 0x00200002L };

static unsigned long SP8[64] = {
	0x10001040L, 0x00001000L, 0x00040000L, 0x10041040L,
	0x10000000L, 0x10001040L, 0x00000040L, 0x10000000L,
	0x00040040L, 0x10040000L, 0x10041040L, 0x00041000L,
	0x10041000L, 0x00041040L, 0x00001000L, 0x00000040L,
	0x10040000L, 0x10000040L, 0x10001000L, 0x00001040L,
	0x00041000L, 0x00040040L, 0x10040040L, 0x10041000L,
	0x00001040L, 0x00000000L, 0x00000000L, 0x10040040L,
	0x10000040L, 0x10001000L, 0x00041040L, 0x00040000L,
	0x00041040L, 0x00040000L, 0x10041000L, 0x00001000L,
	0x00000040L, 0x10040040L, 0x00001000L, 0x00041040L,
	0x10001000L, 0x00000040L, 0x10000040L, 0x10040000L,
	0x10040040L, 0x10000000L, 0x00040000L, 0x10001040L,
	0x00000000L, 0x10041040L, 0x00040040L, 0x10000040L,
	0x10040000L, 0x10001000L, 0x10001040L, 0x00000000L,
	0x10041040L, 0x00041000L, 0x00041000L, 0x00001040L,
	0x00001040L, 0x00040040L, 0x10000000L, 0x10041000L };

static void desfunc(block, keys)
register unsigned long *block, *keys;
{        //block指向的是两个long型单元的数组,存放明文或密文,block[0]存放前4字节，block[1]存放后4字节;
         //keys指向的是32个long型单元的数组，存放密钥，每个单元形式为0x3f3f3f3f.
         
	register unsigned long fval, work, right, leftt;
	register int round;

         /**************************************************************/
         /*****此部分为置换操作       ***********************************/
         /**************************************************************/  
	//比如输入为“abcdefgh”,置换前left=0x61626364,right=0x65666768,置换后结果为left=0xfe00f0ab,right=0x0aff00cc
	leftt = block[0];
	right = block[1];
	work = ((leftt >> 4) ^ right) & 0x0f0f0f0fL;
	right ^= work;
	leftt ^= (work << 4);
	work = ((leftt >> 16) ^ right) & 0x0000ffffL;
	right ^= work;    
	leftt ^= (work << 16);
	work = ((right >> 2) ^ leftt) & 0x33333333L;
	leftt ^= work;
	right ^= (work << 2);
	work = ((right >> 8) ^ leftt) & 0x00ff00ffL;
	leftt ^= work;
	right ^= (work << 8);
	right = ((right << 1) | ((right >> 31) & 1L)) & 0xffffffffL;
	work = (leftt ^ right) & 0xaaaaaaaaL;
	leftt ^= work;
	right ^= work;
	leftt = ((leftt << 1) | ((leftt >> 31) & 1L)) & 0xffffffffL;
	

          /************************************************************************/
          //此部分实际上用了公式的一种变形
          //R[0]->P,所以L[2]=R[1]=P^L[0]
          //R[1]->P',所以R[2]=P'^L[1]=P'^R[0]
          //因此可以每两轮迭代为一组
          /*************************************************************************/
	for( round = 0; round < 8; round++ ) {
		work  = (right << 28) | (right >> 4);//高28位与低4位互换
		work ^= *keys++;             //经过处理的right值与key值进行异或操作
		fval  = SP7[ work & 0x3fL];
		fval |= SP5[(work >>  8) & 0x3fL];
		fval |= SP3[(work >> 16) & 0x3fL];
		fval |= SP1[(work >> 24) & 0x3fL];
		work  = right ^ *keys++;     //经过处理的right值与key值进行异或操作  
		fval |= SP8[ work		 & 0x3fL];
		fval |= SP6[(work >>  8) & 0x3fL];
		fval |= SP4[(work >> 16) & 0x3fL];
		fval |= SP2[(work >> 24) & 0x3fL];
		leftt ^= fval;      //         
		work  = (leftt << 28) | (leftt >> 4);
		work ^= *keys++;
		fval  = SP7[ work		 & 0x3fL];
		fval |= SP5[(work >>  8) & 0x3fL];
		fval |= SP3[(work >> 16) & 0x3fL];
		fval |= SP1[(work >> 24) & 0x3fL];
		work  = leftt ^ *keys++;
		fval |= SP8[ work		 & 0x3fL];
		fval |= SP6[(work >>  8) & 0x3fL];
		fval |= SP4[(work >> 16) & 0x3fL];
		fval |= SP2[(work >> 24) & 0x3fL];
		right ^= fval;
		}
              //下面的部分为前面置换的逆过程
	right = (right << 31) | (right >> 1);
	work = (leftt ^ right) & 0xaaaaaaaaL;
	leftt ^= work;
	right ^= work;
	leftt = (leftt << 31) | (leftt >> 1);
	work = ((leftt >> 8) ^ right) & 0x00ff00ffL;
	right ^= work;
	leftt ^= (work << 8);
	work = ((leftt >> 2) ^ right) & 0x33333333L;
	right ^= work;
	leftt ^= (work << 2);
	work = ((right >> 16) ^ leftt) & 0x0000ffffL;
	leftt ^= work;
	right ^= (work << 16);
	work = ((right >> 4) ^ leftt) & 0x0f0f0f0fL;
	leftt ^= work;
	right ^= (work << 4);
	*block++ = right;
	*block = leftt;
	return;
	}