powmod.cpp

rsa加密过程中需要大数的幂运算后求模

// PowMod.cpp : implementation file
//

#include "stdafx.h"
#include "SoftProtect.h"
#include "PowMod.h"
#include "Superint.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CPowMod dialog


CPowMod::CPowMod(CWnd* pParent /*=NULL*/)
	: CDialog(CPowMod::IDD, pParent)
{
	//{{AFX_DATA_INIT(CPowMod)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
}


void CPowMod::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CPowMod)
		// NOTE: the ClassWizard will add DDX and DDV calls here
	//}}AFX_DATA_MAP
}


BEGIN_MESSAGE_MAP(CPowMod, CDialog)
	//{{AFX_MSG_MAP(CPowMod)
	ON_BN_CLICKED(IDC_BUTTON1, OnButton1)
	ON_BN_CLICKED(IDC_BUTTON2, OnButton2)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CPowMod message handlers

void CPowMod::OnButton1() 
{
	int x = GetDlgItemInt(IDC_EDIT1);
	int y = GetDlgItemInt(IDC_EDIT2);
	int m = GetDlgItemInt(IDC_EDIT3);
	
	CString strX,strY,strM;
	strX.Format(_T("%x"),x);
	strY.Format(_T("%x"),y);
	strM.Format(_T("%x"),m);
	CSuperint siX(strX);
	CSuperint siY(strY);
	CSuperint siM(strM);

	//求结果
	CSuperint siMod(1);

	int iDBits = siY.GetUsedBits();
	CSuperint siBitMod(siX);
	int iDBitModIndex = 0;
	for(int i=0; i<iDBits; i++)
	{
		if(	siY.IsBitOn(i))
		{
			for(int j=iDBitModIndex; j<i; j++)
				siBitMod = siBitMod*siBitMod%siM;
			iDBitModIndex = i;

			siMod = siMod*siBitMod%siM;
		}
	}

	CString strResult;
	int		iResult;
	siMod.GetHex(strResult.GetBufferSetLength(0x1000),0x1000);
	strResult.ReleaseBuffer();

	_stscanf(strResult,_T("%x"),&iResult);
	SetDlgItemInt(IDC_EDIT4,iResult);
}

void CPowMod::OnButton2() 
{
	int x = GetDlgItemInt(IDC_EDIT5);
	int y = GetDlgItemInt(IDC_EDIT6);
	
	CString strX,strY;
	strX.Format(_T("%x"),x);
	strY.Format(_T("%x"),y);
	CSuperint siX(strX);
	CSuperint siY(strY);

	CSuperint siResult = siX%siY;
	CString strResult;
	int		iResult;
	siResult.GetHex(strResult.GetBufferSetLength(0x1000),0x1000);
	strResult.ReleaseBuffer();

	_stscanf(strResult,_T("%x"),&iResult);
	SetDlgItemInt(IDC_EDIT7,iResult);
}