How to make aClaims Viewer WebPart for SP 2013

I have tried to modify existing examples for SP2010 like this:

1. using System;
2. using System.Web.UI;
3. using System.Web.UI.WebControls;
4. using System.Web.UI.WebControls.WebParts;
5. using System.Security.Claims
   
7. namespace ClaimsViewerTest.VisualWebPart1
8. {
9. publicpartialclassVisualWebPart1UserControl :UserControl
10. {
11. protectedvoid Page_Load(object sender,EventArgs e)
12. {
13. ClaimsPrincipal claimsPrincipal = Page.UserasClaimsPrincipal;
14. ClaimsIdentity claimsIdentity = (ClaimsIdentity)claimsPrincipal.Identity;
16. GridView1.DataSource = claimsIdentity.Claims;
17. Page.DataBind();
18. }
19. }
20. }

But then I get object reference not set... when trying to add the webpart in SP2013.

I have also tried instructions on http://blog.helloitsliam.com/Lists/Posts/Post.aspx?ID=80

but then I get assembly generation failed. Referenced assembly ...... does not have a strong name.

If someone could point me to how I can construct the code properly I would be must grateful as a newbie in SP development.