gen.addSigner(_origDsaKP.getPrivate(), _origDsaCert, CMSSignedDataGenerator.DIGEST_SHA1);
gen.addCertificatesAndCRLs(certs);
CMSSignedData s = gen.generate(CMSSignedDataGenerator.DATA, msg, false, "BC", false);
CMSSignedDataParser sp = new CMSSignedDataParser(
new CMSTypedStream(new ByteArrayInputStream(TEST_MESSAGE.getBytes())), s.getEncoded());
sp.getSignedContent().drain();