Content in S/MIME Signed Message

Question

Hi,
In the following statement, is it possible that the content can be a multipart containing two bodyparts (one containing text and one containing file attachment), my question is : the signature is valid ? :
CertStore certs...
SMIMESignedGenerator fact = new SMIMESignedGenerator();
fact.addSigner(privKey, cert, SMIMESignedGenerator.DIGEST_SHA1);
fact.addCertificatesAndCRLs(certs);
MimeMultipart smime = fact.generate(content, "BC");
Example :
MimeBodyPart mbp1 = new MimeBodyPart();
mbp1.setText(mailContent);
mbp1.setHeader("Content-Type", "text/plain");
// Create the attachment and add it to the mail message     
MimeBodyPart mbp2 = new MimeBodyPart();
FileDataSource fileAttachment = new FileDataSource(filePath);
DataHandler dh = new DataHandler(fileAttachment);
mbp2.setDataHandler(dh);
mbp2.setFileName(filename);
mbp2.setHeader("Content-Disposition", "ATTACHMENT");
Multipart multipart = new MimeMultipart("related");
multipart.addBodyPart(mbp1);
multipart.addBodyPart(mbp2);
PrivateKey key = UtilsCrypto.getPrivateKey( alias, passwd, urlpath, keystoretype);
Certificate[] chain = UtilsCrypto.getCertificateChain(alias, passwd, urlpath, keystoretype);
CertStore certsAndCRLs = CertStore.getInstance("Collection", new CollectionCertStoreParameters(Arrays.asList(chain)), "BC");
MimeBodyPart bodyPart = new MimeBodyPart();
X509Certificate cert = (X509Certificate) chain[0];
bodyPart.setContent(multipart);                         
// set up the generator
SMIMESignedGenerator gen = new SMIMESignedGenerator();
gen.addSigner(key, cert, SMIMESignedGenerator.DIGEST_SHA1, null, null);
gen.addCertificatesAndCRLs(certsAndCRLs);
MimeMultipart multipartbase = gen.generate(bodyPart, "BC");
message = setHeadersMessage(message, mailModel, file);
message.setHeader("Content-Type", "Application/pkcs7-signature; smime-type=signed-data;name=smime.p7s");                                                            
message.setContent(multipartbase);                              
message.saveChanges();
trans.sendMessage(message, address);
Many thanks.

Answer 1

Hi,
Okay, this topic is a bit old, nevertheless, here is my response.
If I understand correctly, what you want is to sign a message with attachment.
You can do this with the following code:
// Body object
MimeBodyPart body = new MimeBodyPart();
body.setContent("this is a test yeah", "text/html");
// Attachment
MimeBodyPart attachment = new MimeBodyPart();
attachment.setDataHandler(new DataHandler(new FileDataSource(sendFile), "text/plain"));
attachment.setFileName("blabla.dat");
// Creat MIME message from parts
MimeMessage notyetsigned = new MimeMessage(session);
Multipart multipart = new MimeMultipart();
multipart.addBodyPart(body);
multipart.addBodyPart(attachment);
notyetsigned.setContent(multipart);
/* Sign message */
MimeMultipart mm = gen.generate(notyetsigned, "BC");
// Create signed MIME message (again)
MimeMessage signedmessage = new MimeMessage(session);;
signedmessage.setContent(mm);
// Set up the message instance attributes
signedmessage.addRecipient(Message.RecipientType.TO, new InternetAddress("[email protected]"));
signedmessage.setSubject(subject);
signedmessage.addHeader("X-Priority", "1");
// send message
Transport.send(signedmessage);
Regards,
Valéry B.