public bool MayTrustTo(X509Certificate certificate) { Log.Write("Get authority key"); string authorityId = certificate.GetAuthorityKeyIdentifier(); Log.Write("Got authority key"); Log.Write("Get issuer"); X509Certificate issuerCertificate = GetIssuerCertificate(authorityId); Log.Write("Got issuer"); Log.Write("Check signature"); if (issuerCertificate != null && certificate.IsSignedBy(issuerCertificate)) return true; return false; }