Using credentials based secure string that is disposed

SecureStringTests.cs

using System.Diagnostics;
using System.Linq;
using System.Net;
using System.Security;
using NUnit.Framework;

namespace Tests
{
  [TestFixture]
  public class SecureStringTests
  {
    [Test]
    public void Should_use_credientials_created_with_secure_string_after_it_is_disposed()
    {
      ICredentials credentials;
      var password = "$ome53cure1";

      using (var secure =
        password.Aggregate(
          new SecureString(),
          (ss, c) => { ss.AppendChar(c); return ss; }
        )
      )
      {
        credentials = new NetworkCredential("John.Doe", secure, "MyDomain");
      }
      var wc = new WebClient { Credentials = credentials };
      var result = wc.DownloadString("https://....");

      Trace.Write(result);
    }
  }
}