private void verifySignatures(CMSSignedDataParser sp, byte[] contentDigest)
throws Exception
{
CertStore certStore = sp.getCertificatesAndCRLs("Collection", "BC");
SignerInformationStore signers = sp.getSignerInfos();
Collection c = signers.getSigners();
Iterator it = c.iterator();
while (it.hasNext())
{
SignerInformation signer = (SignerInformation)it.next();