vb.net加密解密方法
1.vb.net加密解密方法
Private Function getLicenseDate() As String Dim b() As Byte Dim path As String = Server.MapPath(Context.Request.ApplicationPath) & "License\" Try If Not System.IO.Directory.Exists(path) Then System.IO.Directory.CreateDirectory(path) End If Catch ex As IO.IOException Page.ClientScript.RegisterStartupScript(Me.GetType(), "Alert", "<script>alert('对不起,你可能没有创建文件夹的权限')</script>") Exit Function End Try Dim output As String Dim filePath As String = path & "License.dat" If File.Exists(filePath) Then Try Dim fs As New FileStream(filePath, FileMode.Open) Dim sr As New StreamReader(fs) output = sr.ReadToEnd().ToString() sr.Close() fs.Close() 'output = Convert.ToBase64String(System.Text.Encoding.Default.GetBytes(filePath)) Catch ex As Exception Page.ClientScript.RegisterStartupScript(Me.GetType(), "Alert", "<script>alert('读取LIENCE文件异常!请取消勾选License文件夹下的License.dat的只读属性!')</script>") End Try Else Exit Function End If Try b = Convert.FromBase64String(output) Catch ex As Exception Page.ClientScript.RegisterStartupScript(Me.GetType(), "Alert", "<script>alert('对不起,,发生错误')</script>") End Try Try output = System.Text.Encoding.GetEncoding(-0).GetString(b) Dim startIndex As Integer = output.IndexOf("<ValidityDate>") + "<ValidityDate>".Length Dim endIndex As Integer = output.IndexOf("</ValidityDate>") Dim index As Integer = endIndex - startIndex If startIndex > 0 And endIndex > 0 And index > 0 Then output = output.Substring(startIndex, index) Else output = "-1" End If Catch ex As Exception Page.ClientScript.RegisterStartupScript(Me.GetType(), "Alert", "<script>alert('获取License信息发生异常')</script>") output = "" End Try Return output End Function
2. viewstate 作用域是本页面