纯c++实现Base64加解密，MFC封装成加解密文件_mfc base64

核心的转换函数：

std::string CMyBase64mfc::base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len)
{
	std::string ret;
	int i = 0;
	int j = 0;
	unsigned char char_array_3[3];
	unsigned char char_array_4[4];
 
	while (in_len--) {
		char_array_3[i++] = *(bytes_to_encode++);
		if (i == 3) {
			char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
			char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
			char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
			char_array_4[3] = char_array_3[2] & 0x3f;
 
			for(i = 0; (i <4) ; i++)
				ret += base64_chars[char_array_4[i]];
			i = 0;
		}
	}
 
	if (i)
	{
		for(j = i; j < 3; j++)
			char_array_3[j] = '\0';
 
		char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
		char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
		char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
		char_array_4[3] = char_array_3[2] & 0x3f;
 
		for (j = 0; (j < i + 1); j++)
			ret += base64_chars[char_array_4[j]];
 
		while((i++ < 3))
			ret += '=';
 
	}
 
	return ret;
}
 
std::string CMyBase64mfc::base64_decode(std::string const& encoded_string)
{
	int in_len = encoded_string.size();
	int i = 0;
	int j = 0;
	int in_ = 0;
	unsigned char char_array_4[4], char_array_3[3];
	std::string ret;
 
	while (in_len-- && ( encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
		char_array_4[i++] = encoded_string[in_]; in_++;
		if (i ==4) {
			for (i = 0; i <4; i++)
				char_array_4[i] = base64_chars.find(char_array_4[i]);
 
			char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
			char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
			char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
 
			for (i = 0; (i < 3); i++)
				ret += char_array_3[i];
			i = 0;
		}
	}
 
	if (i) {
		for (j = i; j <4; j++)
			char_array_4[j] = 0;
 
		for (j = 0; j <4; j++)
			char_array_4[j] = base64_chars.find(char_array_4[j]);
 
		char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
		char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
		char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
 
		for (j = 0; (j < i - 1); j++) ret += char_array_3[j];
	}
 
	return ret;
}

下面是封装的加解密文件的函数。方法就是先打开文件，读取所有字符。

注意这里是按行读取，并且舍弃了换行符。因此读取每一行后要加上换行符再组合起来，base64转换后最后写入文件。

bool CMyBase64mfc::Decode(CString cstrPath)
{
	//读取
	CStdioFile file;
	BOOL flag = file.Open(cstrPath, CFile::modeRead);
	CString ;
	CString text, strline;
	if(flag == FALSE)
	{
		text.Format("读取文件%s失败!", cstrPath);
		UINT uiFlags = MB_OK|MB_SETFOREGROUND|MB_SYSTEMMODAL|MB_ICONINFORMATION;
		MessageBoxTimeout(NULL, text, _T("提示"), uiFlags, 0, 1000);
 
		return false;
	}
 
	file.Seek(0, CFile::begin);
	CString content;
	while(file.ReadString(strline))
	{
		strline += "\n";//加换行符
		content += strline;
	}
 
	file.Close();
 
	//解密
	int iLength = 0;
	std::string base64Content = base64_decode((LPCSTR)(CStringA)content);
 
	//保存
	if (file.Open(cstrPath, CFile::modeCreate | CFile::modeWrite))
	{
		//因为txt中的内容被清空了，所以用begin or end 都可以
		file.Seek(0, CFile::begin);
		file.WriteString(base64Content.c_str());
	}
	else
	{
		UINT uiFlags = MB_OK|MB_SETFOREGROUND|MB_SYSTEMMODAL|MB_ICONINFORMATION;
		MessageBoxTimeout(NULL, _T("文件解密失败！请手动解密！"), _T("提示"), uiFlags, 0, 1000);
		file.Close();
		return true;
	}
 
	file.Close();
	return true;
}
 
bool CMyBase64mfc::Encode(CString cstrPath)
{
	//读取
	CStdioFile file;
	BOOL flag = file.Open(cstrPath, CFile::modeRead);
	CString ;
	CString text, strline;
	if(flag == FALSE)
	{
		text.Format("读取文件%s失败!", cstrPath);
		UINT uiFlags = MB_OK|MB_SETFOREGROUND|MB_SYSTEMMODAL|MB_ICONINFORMATION;
		MessageBoxTimeout(NULL, text, _T("提示"), uiFlags, 0, 1000);
 
		return false;
	}
 
	file.Seek(0, CFile::begin);
	CString content;
	while(file.ReadString(strline))
	{
		strline += "\n";
		content += strline;
	}
 
	file.Close();
 
	//加密
	std::string base64Content = base64_encode((unsigned char*)content.GetBuffer(content.GetLength()), content.GetLength());
 
 
	//保存
	if (file.Open(cstrPath, CFile::modeCreate | CFile::modeWrite))
	{
		//因为txt中的内容被清空了，所以用begin or end 都可以
		file.Seek(0, CFile::begin);
		file.WriteString(base64Content.c_str());
	}
	else
	{
		UINT uiFlags = MB_OK|MB_SETFOREGROUND|MB_SYSTEMMODAL|MB_ICONINFORMATION;
		MessageBoxTimeout(NULL, _T("文件加密失败！请手动加密！"), _T("提示"), uiFlags, 0, 1000);
		file.Close();
		return true;
	}
 
	file.Close();
	return true;
}

测试：

void CMyBase64Dlg::OnBnClickedOk()
{
	// TODO: 在此添加控件通知处理程序代码
	CMyBase64mfc b;
	b.Decode("E:\\myVCProject\\MyBase64\\ReadMe.txt");
 
}
 
 
void CMyBase64Dlg::OnBnClickedCancel()
{
	// TODO: 在此添加控件通知处理程序代码
	CMyBase64mfc b;
	b.Encode("E:\\myVCProject\\MyBase64\\ReadMe.txt");
}

QT下Base64加解密请看

https://blog.csdn.net/qq_24282081/article/details/94906090