internal static void ProcessAttrCert4(
			X509Certificate	acIssuerCert,
			PkixParameters	pkixParams)
		{
			ISet set = pkixParams.GetTrustedACIssuers();
			bool trusted = false;
			foreach (TrustAnchor anchor in set)
			{
                IDictionary symbols = X509Name.RFC2253Symbols;
                if (acIssuerCert.SubjectDN.ToString(false, symbols).Equals(anchor.CAName)
					|| acIssuerCert.Equals(anchor.TrustedCert))
				{
					trusted = true;
				}
			}
			if (!trusted)
			{
				throw new PkixCertPathValidatorException(
					"Attribute certificate issuer is not directly trusted.");
			}
		}