ayLen) = Chr(124)
        all_char(ArrayLen+1) = Chr(126)
        ArrayLen = ArrayLen + 2
    End If
    If ArrayLen = 0 Then
        MsgBox "错误：没有选择'密码使用的字符'", , "请选择密码使用的字符范围..."
        Exit Sub
    End If
    If blnProcessing Then
        If MsgBox("真的要中断解密过程吗？", vbYesNo, "用户中断任务") = vbYes Then blnProcessing = False
    Else
        CmdStartCrack.Caption = "中断破解"
        blnProcessing = True
        strpath = Combo1.Text
        If strpath = "" Then
            MsgBox "错误：没有选择'需要解密的文件'", , "请选择需要解密的文件..."
            Exit Sub
        End If
        strpath = Trim(strpath)
        Password_Start_Long = Val(txtPasswordStartLong.Text)
        Password_End_Long = Val(txtPasswordEndLong.Text)
        If Password_Start_Long > Password_End_Long Then
            Password_Start_Long = Val(txtPasswordEndLong.Text)
            Password_End_Long = Val(txtPasswordStartLong.Text)
        End If
        Label1.Caption = "破解进度："
        Label1.Refresh
        On Error Resume Next
        If UCase(Right(strpath, 3)) = "XLS" Then
            For K = Password_Start_Long To Password_End_Long    '破解excel开始
                For I = 0 To ArrayLen ^ K - 1
                    pass = ""
                    Temp = I
                    For J = 1 To K - 1
                        Temp = Temp \ ArrayLe
                        pass = all_char(Temp Mod ArrayLen) + pass
                    Next J
                    pass = pass + all_char(I Mod ArrayLen)
                    Set OpenReturn = xls.Workbooks.Open(FileName:=strpath, Password:=pass)
                    Text1.Text = pass    '显示破解进度
                    Text1.Refresh
                    If Err.Number <> 0 Then  '如果解密成功,打开文档,显示密码,退出过程
                        Err.Clear
                    Else
                        Label1.Caption = "文档密码："
                        Text1.Text = pass
                        Me.Refresh
                        xls.Visible = True
                        CmdStartCrack.MousePointer = 0
                        CmdStartCrack.Caption = "开始破解"
                        blnProcessing = False
                        Set xls = Nothing
                        Exit Sub
                    End If
                    DoEvents
                    If Not blnProcessing Then Exit For
                Next I
                If Not blnProcessing Then Exit For
            Next K
            xls.Quit
            Set xls = Nothing
        Else
            For K = Password_Start_Long To Password_End_Long  '破解word开始
                For I = 0 To ArrayLen ^ K - 1
                    pass = ""
                    Temp = I
                    For J = 1 To K -
                      Temp = Temp \ ArrayLen
                        pass = all_char(Temp Mod ArrayLen) + pass
                    Next J
                    pass = pass + all_char(I Mod ArrayLen)
                    OpenReturn = wd.Documents.Open(FileName:=strpath, passworddocument:=pass)
                    Text1.Text = pass  '显示破解进度
                    Text1.Refresh
                    If Err.Number <> 0 Then    '如果解密成功,打开文档,显示密码,退出过程
                        Err.Clear
                    Else
                        'MsgBox "word password"
                        Label1.Caption = "文档密码："
                        Text1.Text = pass
                        Me.Refresh
                        wd.Visible = True
                        CmdStartCrack.MousePointer = 0
                        CmdStartCrack.Caption = "开始破解"
                        blnProcessing = False
                        Set wd = Nothing
                        Exit Sub
                    End If
                    DoEvents
                    If Not blnProcessing Then Exit For
                Next I
                If Not blnProcessing Then Exit For
            Next K
            wd.Quit
            Set wd = Nothing
        End If
        CmdStartCrack.Caption = "开始破解"
        If blnProcessing Then MsgBox "没有找到密码，可能是密码位数不对!", , "提示信息..."
        blnProcessing = False
End Sub
3. 时间复杂度分析
一个算法的时间复杂度，是指该算法的时间耗费，是该算法所求解问题规模n的函数。根据前面讲的实现原理，我们知道，破解算法的时间耗费主要集中在尝试打开OFFICE文档上，因此，当我们假设破解一个N位字符串密码，且选定密码字符范围的总字符数为ArrayLen时，该算法的时间复杂度是O(ArrayLen^N)。即，当N确定后，该算法的时间复杂度是N次方阶；当ArrayLen确定后，该算法的时间复杂度是指数阶。都是高数量级的时间复杂度。
4. 说明
穷举法解密对系统资源的占用是十分惊人的，在解密的过程中最好不要运行其他应用程序。如果安装有瑞星等杀毒软件，应将杀毒软件的“office安全助手”去掉，以便加快程序的运行速度。
该程序在WinXP+OfficeXP+VB6.0环境下测试通过，笔者随便测试了一个5位数字密码，在P4机器上，8分钟左右即可解开口令。

 

 

参考文献：
[1] 王建华 译. Visual Basic 6 开发人员指南.  北京：机械工业出版社，1999