public void AsymmetricSignatureProvider_Dispose()
        {
            AsymmetricSignatureProvider provider = new AsymmetricSignatureProvider(KeyingMaterial.DefaultAsymmetricKey_Public_2048, SecurityAlgorithms.RsaSha256Signature);
            provider.Dispose();

            ExpectedException expectedException = ExpectedException.ObjectDisposedException;
            try
            {
                provider.Sign(new byte[256]);
            }
            catch (Exception ex)
            {
                expectedException.ProcessException(ex);
            }

            try
            {
                provider.Verify(new byte[256], new byte[256]);
            }
            catch (Exception ex)
            {
                expectedException.ProcessException(ex);
            }

            try
            {
                provider.Dispose();
            }
            catch (Exception ex)
            {
                Assert.Fail(string.Format("AsymmetricSignatureProvider.Dispose called twice, caught exception: '{0}'", ex));
            }
        }