ASN1EncodableVector signedAttrs = generateSignedAttributes();
SMIMESignedGenerator gen = new SMIMESignedGenerator();
gen.addSigner(_signKP.getPrivate(), _signCert, SMIMESignedGenerator.DIGEST_SHA224, new AttributeTable(signedAttrs), null);
gen.addCertificatesAndCRLs(certs);
MimeMultipart smm = gen.generate(msg, "BC");
SMIMESignedParser s = new SMIMESignedParser(smm);
certs = s.getCertificatesAndCRLs("Collection", "BC");