如何隐藏数据库密码？

doocoo 2009-07-17 10:17:00

我在用C#+SQL Server Compact Edition做一个程序。现在有个问题是：数据库文件不能被用户直接打开，所以要设定一个密码。但密码写在哪里呢？如果写在工程properties的connectstring里面或写在代码里面，都很容易用反编译工具ILDASM等看到。即便用模糊化处理，细心一点还是能找到的。
怎么办？这个问题应该和所有加密数据库都有关。

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xhueducls 2009-07-17

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.NET的反破解本来就不是很强，只有这样了

doocoo 2009-07-17

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[Quote=引用 8 楼 zhiyu19 的回复:]
给你两个例子吧，你参考一下
[/Quote]

谢谢，不过你这个方法，基础是SQL Server，但我要用的是SQL Server CE,是文件型的数据库，数据文件是在客户端的。我是担心数据文件被直接打开。
如果用你这个方法来加密Password，那人家一反编译，就知道你是怎么加密的了，解密也就很简单。

zhiyu19 2009-07-17

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给你两个例子吧，你参考一下
加密：



using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Data.SqlClient;

using System.Xml;

using System.IO;

using System.Text;



public partial class _Default : System.Web.UI.Page 

{

    protected void Page_Load(object sender, EventArgs e)

    {

        string strCon = "Data Source=(local);Database=db_15;Uid=sa;Pwd=";

        SqlConnection sqlcon = new SqlConnection(strCon);

        string sqlstr = "select * from tb_Employee";

        SqlDataAdapter myda = new SqlDataAdapter(sqlstr, strCon);

        DataSet myds = new DataSet();

        sqlcon.Open();

        myda.Fill(myds);

        sqlcon.Close();

        myds.WriteXml("test.xml");

        XmlDocument doc = new XmlDocument();

        doc.Load("test.xml");

        Xml1.Document = doc;

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        Label1.Visible = true;

        FileStream oldXml = new FileStream(test.xml",FileMode.OpenOrCreate,FileAccess.Read,FileShare.Read);

        EncodeXml("testNew.xml",oldXml);

        XmlDocument doc1 = new XmlDocument();

        doc1.Load("test.xml");

        Xml1.Document = doc1;

        XmlDocument doc2 = new XmlDocument();

        doc2.Load("testNew.xml");

        Xml2.Document = doc2;

        Button1.Enabled = false;

    }

    public void EncodeXml(string newXml, FileStream oldXml)

    {

        byte[] buffer = new byte[1024]; ;

        int readbyte = 0;

        XmlTextWriter xw = new XmlTextWriter(newXml,Encoding.UTF8);

        xw.WriteStartDocument();

        xw.WriteStartElement("root");

        BinaryReader br = new BinaryReader(oldXml);

        do

        {

            readbyte = br.Read(buffer,0,1024);

            xw.WriteBase64(buffer,0,readbyte);

        }

        while (1024 <= readbyte);

        xw.WriteEndElement();

        xw.WriteEndDocument();

        xw.Flush();

        xw.Close();

    }

}

解密：



using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Data.SqlClient;

using System.Xml;

using System.IO;

using System.Text;



public partial class _Default : System.Web.UI.Page 

{

    protected void Page_Load(object sender, EventArgs e)

    {

        XmlDocument doc = new XmlDocument();

        doc.Load("test.xml");

        Xml1.Document = doc;

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        Label1.Visible = true;

        FileStream newXml = new FileStream("testNew.xml",FileMode.Create,FileAccess.ReadWrite,FileShare.ReadWrite);

        decodeXml("test.xml",newXml);

        XmlDocument doc = new XmlDocument();

        doc.Load("testNew.xml");

        Xml2.Document = doc;

    }

    public void decodeXml(string oldXml, FileStream newXml)

    {

        byte[] buffer = new byte[1024]; ;

        int readbyte = 0;

        BinaryWriter bw = new BinaryWriter(newXml);

        XmlTextReader tr = new XmlTextReader(oldXml);

        tr.MoveToContent();

        do

        {

            readbyte = tr.ReadBase64(buffer, 0, 1024);

            bw.Write(buffer, 0, readbyte);

        }

        while (1024 <= readbyte);

        bw.Flush();

        bw.Close();

    }

}

xml文件也顺便发给你吧
<?xml version="1.0" standalone="yes"?>
<NewDataSet>
<Table>
<EmployeeID>2</EmployeeID>
<EName>张三</EName>
<ESex>男</ESex>
<EAge>28</EAge>
<EPlace>北京市</EPlace>
<EMoney>3000</EMoney>
</Table>
<Table>
<EmployeeID>3</EmployeeID>
<EName>李四</EName>
<ESex>女</ESex>
<EAge>23</EAge>
<EPlace>上海市</EPlace>
<EMoney>3000</EMoney>
</Table>
<Table>
<EmployeeID>4</EmployeeID>
<EName>王五</EName>
<ESex>女</ESex>
<EAge>26</EAge>
<EPlace>天津市</EPlace>
<EMoney>2000</EMoney>
</Table>
</NewDataSet>

doocoo 2009-07-17