日期:2014-05-18  浏览次数:21254 次

*****用代码给access数据库加密..怎么实现?
如题:

用代码给access数据库加密..怎么实现?
用代码给access数据库加密..怎么实现?

------解决方案--------------------
把MDB文件以二进制XOR
把access文件保存为其他自定义格式
http://www.codeproject.com/KB/files/encryption.aspx
------解决方案--------------------
C# code
//根据网上经验和方法用C#做一个破解程序
  // 本程序最多取16位密码
  using System.IO;
  using System.Windows.Forms;
  class Access
  {
  // 获取密码
  static string GetPassword(string file)
  { // 未加密的文件0x42开始至0x61之前的每间隔一字节的数值
   byte[] baseByte = { 0xbe,0xec,0x65,0x9c,0xfe,0x28,0x2b,0x8a,0x6c,0x7b,0xcd,0xdf,0x4f,0x13,0xf7,0xb1, };
   byte flagByte = 0x0c; // 标志 0x62 处的数值
   string password = \"\";
   try
   {
    FileStream fs = File.OpenRead(file);
   fs.Seek(0x14, SeekOrigin.Begin);
    byte ver = (byte)fs.ReadByte(); // 取得版本, 1为Access2000, 0为Access97
    fs.Seek(0x42, SeekOrigin.Begin);
    byte[] bs = new byte[33];
    if (fs.Read(bs, 0, 33) != 33) return \"\";
    byte flag = (byte)(bs[32] ^ flagByte);
    for(int i = 0; i < 16; i++)
    {
  byte b = (byte)(baseByte^bs[i*2]);
  if (i%2==0 && ver==1) b ^= flag; //Access 2000
  if (b > 0) password += (char)b;
    }
   }
   catch {}
   return password;
  }
  // 主入口
  static void Main()
  {
   OpenFileDialog f = new OpenFileDialog();
   if (f.ShowDialog() != DialogResult.OK) return;
   MessageBox.Show(\"密码:[\" + GetPassword(f.FileName) + \"]\", \"密码\");
  }
  }

------解决方案--------------------
VB code

Private Function ChangeAccessPwd(ByVal OldPassword As String, ByVal NewPassword As String, ByVal DbPath As String) As Boolean
    On Error GoTo ErrorHandler

    Dim db As DAO.Database, ws As DAO.Workspace

    Set ws = DBEngine.Workspaces(0)
    Set db = ws.OpenDatabase(DbPath, True, False, "MS Access;PWD=" & OldPassword)

    'Change password
    db.NewPassword OldPassword, NewPassword

    db.Close: Set db = Nothing
    ws.Close: Set ws = Nothing
    ChangeAccessPwd = True

Exit Function

ErrorHandler:
    Set db = Nothing
    Set ws = Nothing

    ChangeAccessPwd = False

End Function
ACCESS密码容易被破解。。