dblock.cpp

椭圆曲线密码C实现的

// DBlock.cpp: implementation of the CDBlock class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "DBlock.h"

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CDBlock::CDBlock(vlong	n)
{
	m_uBits = 0;
	if(n != vlong(0))
	{
		m_n = n ;
		m_uBits = m_n.m_pValue->GetBits()-1;	//单个明文块的最大位数
	}

	m_pMBuf = NULL;
}

CDBlock::~CDBlock()
{
	if(m_pMBuf != NULL)
		delete []m_pMBuf;
}


int CDBlock::MToDigist(unsigned char*	pMBuf,unsigned 	uLen)
{

	m_pMBuf = new unsigned char[2*uLen];

	if(pMBuf == NULL || uLen == 0)
		return 1;
	
	unsigned  off = 0 , i = 0,t1 ;
	unsigned char *pMov = pMBuf;
	vlong blk;
	
	t1 = i;
	while(i < uLen)
	{
		t1 = i;				
		t1 += (m_uBits + off)/8;
		if(t1 >= uLen)
			break;
		pMov= pMBuf + i;		
		blk	=	DigitToVLInt(pMov,off,m_uBits);	

		unsigned d = blk;
		i	=	t1;		
		off =	(m_uBits + off)%8;
	};

	pMov= pMBuf + i;
	unsigned x = ((uLen - i)*8-off) ;
	blk	=	DigitToVLInt(pMov,off,x);	
	return 0;
}


//----------------------------------------------------------
vlong CDBlock::DigitToVLInt(unsigned char *pBuf, unsigned uOff, unsigned uBits)
{
	vlong	theResult;
	unsigned char *	pMove;
	unsigned short	Tmp;
	unsigned char *	pTmp;
	unsigned uR;

	uR = 0;
	pMove = pBuf;
	pTmp = (unsigned char*)&Tmp;
	
	while( (uR + 16) < uBits)
	{
		*pTmp	   = (*pMove)<<uOff;
		*pTmp	  |= (*(++pMove))>>(8-uOff);
		*(pTmp+1)  = (*pMove)<<uOff;
		*(pTmp+1) |= (*(++pMove))>>(8-uOff);
		theResult.m_pValue->Append(Tmp);
		uR += 16;
	}
	Tmp = 0;

	if((uR+8) < uBits)
	{
		*pTmp	 =	(*pMove)<<uOff;
		*pTmp	|=	(*(++pMove))>>(8-uOff);
		uR+=8;
		pTmp++;
	}
	
	unsigned char uch;
	if((uOff+(uBits - uR))<8)
	{
		uch = *pMove;
		ushort x= (8 - uBits + uR - uOff);
		uch &= ((0xff>>x)<<(x+uOff));
		*pTmp = uch<<uOff;

	}else{
		*pTmp = (*pMove<<uOff);
		uch = *(pMove+1);
		uch &= (0xff <<(16 - uBits + uR - uOff));
		*pTmp = (uch >>(8- uOff));
	}

	uR += ((uBits+uOff)%8);

	theResult.m_pValue->Append(Tmp);
	theResult.m_pValue->ReArray();	//整理数据

	return theResult;

}