Is there a library or a way to do this without an external library? I am using apache james as my mail server and currently send email like this:
public void sendMessage(String to, String subject, String content) {
MimeMessage message = new MimeMessage(session);
try {
message.addRecipients(Message.RecipientType.TO, to);
message.setFrom(new InternetAddress(from));
message.setSubject(subject);
message.setContent(content, "text/html; charset=utf-8");
Transport.send(message);
} catch (MessagingException e) {
e.printStackTrace();
}
}
But i'd like to sign the email with DKIM before hand. I understand I need to implement DKIM signing into the james server and plan on use jDKIM to do this, I also understand I need to create the keys using something like www.port25.com, but how do I actually sign the email in java before I send it out?
I ended up using DKIM for Javamail which can be downloaded at: DKIM For Javamail
Here is an example (Its pretty well documented in the examples in the download):
public void sendMessage(String to, String subject, String content) {
//Create DKIM Signer
DKIMSigner dkimSigner = null;
try {
dkimSigner = new DKIMSigner(properties.getProperty("mail.smtp.dkim.signingdomain"), properties.getProperty("mail.smtp.dkim.selector"), properties.getProperty("mail.smtp.dkim.privatekey"));
dkimSigner.setIdentity(properties.getProperty("mail.user") + "@" + properties.getProperty("mail.smtp.dkim.signingdomain"));
dkimSigner.setHeaderCanonicalization(Canonicalization.SIMPLE);
dkimSigner.setBodyCanonicalization(Canonicalization.RELAXED);
dkimSigner.setLengthParam(true);
dkimSigner.setSigningAlgorithm(SigningAlgorithm.SHA1withRSA);
dkimSigner.setZParam(true);
} catch (Exception e) {
e.printStackTrace();
}
if(dkimSigner != null) {
//Create message
Message message = new SMTPDKIMMessage(session, dkimSigner);
try {
message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to, false));
message.setFrom(new InternetAddress(from));
message.setSubject(subject);
message.setContent(content, "text/html; charset=utf-8");
Transport.send(message);
} catch (MessagingException e) {
e.printStackTrace();
}
}
}