//
MimeBodyPart mp = gen.generate(_msg, SMIMEEnvelopedGenerator.RC2_CBC, 40, "BC");
SMIMEEnveloped m = new SMIMEEnveloped(mp);
RecipientId recId = new RecipientId();
dig.update(_reciCert.getPublicKey().getEncoded());
recId.setSubjectKeyIdentifier(dig.digest());
RecipientInformationStore recipients = m.getRecipientInfos();
RecipientInformation recipient = recipients.get(recId);
MimeBodyPart res = SMIMEUtil.toMimeBodyPart(recipient.getContent(_reciKP.getPrivate(), "BC"));