/**
* Find the issuer certificates of a given certificate.
*
* @param cert
* The certificate for which an issuer should be found.
* @param pkixParams
* @return A <code>Collection</code> object containing the issuer
* <code>X509Certificate</code>s. Never <code>null</code>.
*
* @exception Exception
* if an error occurs.
*/
internal static ICollection FindIssuerCerts(
X509Certificate cert,
PkixBuilderParameters pkixParams)
{
X509CertStoreSelector certSelect = new X509CertStoreSelector();
ISet certs = new HashSet();
try
{
certSelect.Subject = cert.IssuerDN;
}
catch (IOException ex)
{
throw new Exception(
"Subject criteria for certificate selector to find issuer certificate could not be set.", ex);
}
try
{
certs.AddAll(PkixCertPathValidatorUtilities.FindCertificates(certSelect, pkixParams.GetStores()));
certs.AddAll(PkixCertPathValidatorUtilities.FindCertificates(certSelect, pkixParams.GetAdditionalStores()));
}
catch (Exception e)
{
throw new Exception("Issuer certificate cannot be searched.", e);
}
return(certs);
}
