StrongNameIdent ityPermission Permission

[David Riddiford]

Hi

I am trying to protect a class from being used by anything other than the application for which it was intended with StrongNameIdent ityPermission using declarative code access security

In my solution, I have a Windows Forms Project called MainApp which I have signed with a strong name key. I also have a Class Library Project called CallClass, which I have signed with the same key

CallClass contains one class called MyClass which is coded as follows :

[StrongNameIdent ityPermission(S ecurityAction.L inkDemand, PublicKey="<pub lic key>", Name="MainApp.e xe", Version="1.0.0. 0")
public class MyClas

public MyClass(

public static string LogonSucceed(

return "This message indicates the logon process succeeded."

I obtained the public key by running sn -Tp against the .snk file

MainApp has a reference to CallClass, and contains 1 Win Form called MainForm. The Load Event for MainForm is coded as follows :

private void MainForm_Load(o bject sender, System.EventArg s e

try

MessageBox.Show (MyClass.LogonS ucceed())

catch (SecurityExcept ion ex

MessageBox.Show ("MyClass is unavailable. " + ex.Message)
Application.Exi t()

When I run this app in VS.NET 2003, I receive the following error :
Request for the permission of type System.Security .Permissions.St rongNameIdentit yPermission, mscorlib, Version=1.0.500 0.0, Culture=neutral , PublicKeyToken= <public key token> failed

Note that the stack trace for the exception and manual tracing indicate that the exception occurs before any code within MainForm_Load is actually run

My understanding is that an exception will occur when you specify a Security Action of Demand in the attribute, because a full stack walk is performed and all callers, all the way back to mscorlib are expected to have been signed with the same strong name key

However, I am using LinkDemand, which should only require the immediate caller to be signed with the key

Note that I have also posted this one to the dotnet.security group. But I thought I'd post it here too just in case

Any help you could provide to solve this problem would be much appreciated

Thanks
David Riddiford