異或加密工具類

寫了一個異或加密工具類

• 呼叫加密字串
• 直接加密檔案

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>

using namespace std;

class Encrypt
{
public:
	// 建構式
	Encrypt();
	Encrypt(char *pContent, unsigned char ucKey = 'x');

	// 拷貝建構式
	Encrypt(const Encrypt& e);
	// 多載賦值運算子
	Encrypt& operator=(const Encrypt& e);
	// 解構式
	~Encrypt();
public:
	// 更新密匙
	void ChangeKey(unsigned char ucNewKey)
	{
		m_ucKey = ucNewKey;
	}
	// 獲取密匙
	unsigned char GetKey() const 
	{
		return(m_ucKey);
	}
public:
	// 加密檔案
	bool CryptFile(const char* pszFileName);
	// 加密字串(在原字串上修改)
	bool CryptString(char *pszStr);
	// 加密字串, 給定字串長度(在原字串上修改)
	bool CryptString(char *pszFile, size_t nSize);
	// 分配新的空間并在此基礎上加密 (不變動原字串)
	bool CryptString(const char *pszStr, char **ppszNewStr);

private:
	// 以wb+方式打開檔案
	FILE *OpenTheFile(const char *pszFileName);
	// 寫入檔案的封裝
	size_t WriteToFile(const char *pszFileName, const char *pszStr);
	size_t WriteToFile(const char* pszFileName, const char* pszStr, size_t nSize);
	// 讀取檔案
	size_t ReadFromFile(const char *pszFileName, char **ppszBuf);
	// 獲取檔案大小
	size_t GetFileSize(const char* pszFileName);
private:
	// 只有加密字串時才會使用該成員, 加密檔案該成員不使用
	char* m_pContent;
	unsigned char m_ucKey;
};

Encrypt::Encrypt() : m_pContent(nullptr), m_ucKey('x')
{

}

Encrypt::Encrypt(char* pContent, unsigned char ucKey /*= 'x'*/)
{
	size_t nSize = 0;

	if (nullptr != pContent)
	{
		nSize = strlen(pContent);

		// 獲取密匙
		if (ucKey != 'x')
		{
			m_ucKey = ucKey;
		}
		// 分配內容并拷貝
		m_pContent = new char[nSize + 1];
		memset(m_pContent, 0, nSize + 1);
		strcpy(m_pContent, pContent);
	}
	else
	{
		// 如果傳入字串為nullptr直接賦空
		m_pContent = nullptr;
		m_ucKey = ucKey;
	}
}

Encrypt::Encrypt(const Encrypt& e)
{
	size_t nSize = 0;

	if (nullptr != e.m_pContent)
	{
		nSize = strlen(e.m_pContent);
		
		// 獲取秘鑰
		m_ucKey = e.m_ucKey;
		// 內容復制
		m_pContent = new char[nSize + 1];
		memset(m_pContent, 0, nSize + 1);
		strcpy(m_pContent, e.m_pContent);
	}
	else
	{
		m_pContent = nullptr;
		m_ucKey = e.m_ucKey;
	}
}

Encrypt& Encrypt::operator=(const Encrypt& e)
{
	// 原空間是否有內容，有就釋放掉
	if (nullptr != m_pContent)
	{
		delete[] m_pContent;
		m_pContent = nullptr;
	}
	// 檢查目標物件是否為Null, 是就直接復制密匙就回傳, 不是則拷貝內容
	if (nullptr != e.m_pContent)
	{
		// 如果目標物件由內容則拷貝內容
		size_t nSize = strlen(e.m_pContent);
		m_pContent = new char[nSize + 1];
		strcpy(m_pContent, e.m_pContent);
	}
	m_ucKey = e.m_ucKey;

	return(*this);
}

Encrypt::~Encrypt()
{
	if (nullptr != m_pContent)
	{
		delete[] m_pContent;
		m_pContent = nullptr;
	}
}

bool Encrypt::CryptString(char* pszStr)
{
	size_t nSize = 0;

	if (nullptr == pszStr)
	{
		cout << "Encrypt::CryptString引數不能為nullptr" << endl;
		return(false);
	}
	nSize = strlen(pszStr);
	// 執行xor加密程序
	for (size_t nIdx = 0; nIdx < nSize; ++nIdx)
	{
		*(pszStr + nIdx) ^= m_ucKey;
	}

	return(true);
}

bool Encrypt::CryptString(char* pszFile, size_t nSize)
{
	if ((nullptr == pszFile) || (nSize == 0))
	{
		cout << "Encrypt::CryptFile的引數錯誤" << endl;
		return(false);
	}
	for (size_t nIdx = 0; nIdx < nSize; ++nIdx)
	{
		*(pszFile + nIdx) ^= m_ucKey;
	}

	return(true);
}

bool Encrypt::CryptString(const char* pszStr, char** ppszNewStr)
{
	char* pBuf = nullptr;
	size_t nSize = 0;
	bool fOk = false;

	if ((nullptr == pszStr) || (nullptr == ppszNewStr))
	{
		cout << "Encrypt::CryptString引數不能為nullptr" << endl;
		return(false);
	}
	nSize = strlen(pszStr);

	pBuf = new char[nSize + 1];
	memset(pBuf, 0, nSize + 1);
	memcpy(pBuf, pszStr, nSize);

	// 加密字串
	fOk = CryptString(pBuf);
	if (false == fOk)
	{
		cout << "Encrypt::CryptString的多載中CryptString失敗" << endl;
		delete[] pBuf;

		return(fOk);
	}
	*ppszNewStr = pBuf;

	return(fOk);
}

FILE* Encrypt::OpenTheFile(const char* pszFileName)
{
	FILE* fp = nullptr;
	 
	if (nullptr == pszFileName)
	{
		cout << "Encrypt::OpenTheFile 引數不能為nullptr" << endl;
		return(nullptr);
	}
	fp = fopen(pszFileName, "rb+");
	if (nullptr == fp)
	{
		cout << "Encrypt::OpenTheFile中fopen失敗" << endl;
		return(nullptr);
	}

	return(fp);
}

size_t Encrypt::WriteToFile(const char* pszFileName, const char* pszStr)
{
	FILE* fp = nullptr;
	size_t nSize = 0;
	size_t nWriteIn = 0;

	if ((nullptr == pszFileName) || (nullptr == pszStr))
	{
		cout << "Encrypt::WriteToFile 引數不能為nullptr";
		return(0);
	}
	fp = fopen(pszFileName, "wb");
	if (nullptr == fp)
	{
		cout << "Encrypt::WriteToFile中OpenTheFile失敗" << endl;
		return(0);
	}
	nSize = strlen(pszStr);
	if (nSize != (nWriteIn = fwrite(pszStr, 1, nSize, fp)))
	{
		cout << "Encrypt::WriteToFile中fwrite失敗" << endl;
		nWriteIn = 0;
	}
	fclose(fp);

	return(nWriteIn);
}

size_t Encrypt::WriteToFile(const char* pszFileName, const char* pszStr, size_t nSize)
{
	FILE* fp = nullptr;
	size_t nWriteIn = 0;

	if ((nullptr == pszFileName) || (nullptr == pszStr) || (nSize == 0))
	{
		cout << "Encrypt::WriteToFile 引數不能為nullptr";
		return(0);
	}
	fp = fopen(pszFileName, "wb");
	if (nullptr == fp)
	{
		cout << "Encrypt::WriteToFile中OpenTheFile失敗" << endl;
		return(0);
	}
	if (nSize != (nWriteIn = fwrite(pszStr, 1, nSize, fp)))
	{
		cout << "Encrypt::WriteToFile中fwrite失敗" << endl;
		nWriteIn = 0;
	}
	fclose(fp);

	return(nWriteIn);
}

size_t Encrypt::ReadFromFile(const char* pszFileName, char** ppszBuf)
{
	size_t nSize = 0;
	size_t nSizeRead = 0;
	FILE* fp = nullptr;
	char* pBuf = nullptr;

	if ((nullptr == pszFileName) || (nullptr == ppszBuf))
	{
		cout << "Encrypt::ReadFromFile引數不能是nullptr" << endl;
		return(0);
	}
	// 獲取檔案大小
	nSize = GetFileSize(pszFileName);
	// 打開檔案
	fp = OpenTheFile(pszFileName);
	if (nullptr == fp)
	{
		cout << "Encrypt::ReadFromFile的OpenTheFile()失敗!" << endl;
		return(0);
	}
	// 分配空間
	pBuf = new char[nSize + 1];
	memset(pBuf, 0, nSize + 1);

	// 讀取檔案內容到分配的堆空間中
	if (nSize != (nSizeRead = fread(pBuf, 1, nSize, fp)))
	{
		delete[] pBuf;
		pBuf = nullptr;
		cout << "Encrypt::ReadFromFile中fread失敗" << endl;
		fclose(fp);

		return(0);
	}
	*ppszBuf = pBuf;
	fclose(fp);

	return(nSizeRead);
}

size_t Encrypt::GetFileSize(const char* pszFileName)
{
	FILE* fp = nullptr;
	long lSizeOfFile = 0;
	if (nullptr == pszFileName)
	{
		cout << "Encrypt::GetFileSize引數不能是nullptr" << endl;
		return(0);
	}
	// 打開檔案
	fp = OpenTheFile(pszFileName);
	if (nullptr == fp)
	{
		cout << "Encrypt::GetFileSize中OpenTheFile失敗" << endl;
		return(0);
	}
	// 走到末尾
	fseek(fp, 0L, SEEK_END);
	// 獲取大小
	lSizeOfFile = ftell(fp);
	fclose(fp);

	return((size_t)lSizeOfFile);
}

bool Encrypt::CryptFile(const char* pszFileName)
{
	size_t nSize = 0;
	char* pBuf = nullptr;
	bool fOk = true;

	if (nullptr == pszFileName)
	{
		cout << "Encrypt::CryptFile中引數是nullptr" << endl;
		return(false);
	}
	// 讀取檔案內容
	nSize = ReadFromFile(pszFileName, &pBuf);
	if (0 == nSize)
	{
		cout << "Encrypt::CryptFile中ReadFromFile失敗!" << endl;
		return(false);
	}
	// 加密檔案內容
	fOk = CryptString(pBuf, nSize);
	
	if (true == fOk)
	{
		// 保存檔案內容到原檔案
		nSize = WriteToFile(pszFileName, pBuf, nSize);
		if (0 != nSize)
		{
			// 成功, 釋放空間
			delete[] pBuf;
			pBuf = nullptr;
			return(true);
		}
		else
		{
			cout << "Encrypt::CryptFile中WriteToFile失敗!" << endl;
		}
	}
	else
	{
		cout << "Encrypt::CryptFile中CryptString失敗!" << endl;
	}
	delete[] pBuf;
	pBuf = nullptr;

	return(false);
}


int main()
{
	Encrypt e;

	system("pause");

	return(0);
}

(完)