internal unsafe void AddCountersignature(CmsSigner cmsSigner, CngKey privateKey)
{
using (var hb = new HeapBlockRetainer())
{
var signerInfo = NativeUtility.CreateSignerInfo(cmsSigner, privateKey, hb);
NativeUtility.ThrowIfFailed(NativeMethods.CryptMsgCountersign(
_handle,
dwIndex: 0,
cCountersigners: 1,
rgCountersigners: signerInfo));
AddCertificates(CertificateUtility.GetRawDataForCollection(cmsSigner.Certificates));
}
}