(Java) POP3 Verify Signed (S/MIME) Email

Demonstrates how to download and verify digitally signed S/MIME email.

Chilkat Java Downloads Java Libs for Windows, MacOS, Linux, Alpine Linux, Solaris Java Libs for Android

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkMailMan mailman = new CkMailMan();
    boolean success;

    // Set the POP3 server's hostname
    mailman.put_MailHost("pop.someMailServer.com");

    // Set the POP3 login/password.
    mailman.put_PopUsername("myLogin");
    mailman.put_PopPassword("myPassword");

    CkStringArray sa = mailman.GetUidls();
    if (mailman.get_LastMethodSuccess() == false) {
        System.out.println(mailman.lastErrorText());
        return;
        }

    CkEmail email;
    String uidl;

    int i = 0;
    while (i < sa.get_Count()) {

        uidl = sa.getString(i);

        email = mailman.FetchEmail(uidl);
        if (mailman.get_LastMethodSuccess() == false) {
            System.out.println(mailman.lastErrorText());

            return;
            }

        System.out.println(email.ck_from());
        System.out.println(email.subject());

        // The security layers of signed and/or encrypted emails
        // are automatically "unwrapped" when loaded into
        // a Chilkat email object.
        // An application only needs to check to see if an email
        // was received signed or encrypted, and then examine
        // the success/failure.  For example:
        if (email.get_ReceivedSigned() == true) {

            System.out.println("This email was signed.");

            // Check to see if the signatures were verified.
            if (email.get_SignaturesValid() == true) {
                System.out.println("Digital signature(s) verified.");
                System.out.println("Signer: " + email.signedBy());

                // The certificate used for signing may be obtained
                // by calling email.GetSignedByCert.
                CkCert cert;
                cert = email.GetSignedByCert();
                if (email.get_LastMethodSuccess() == false) {
                    System.out.println("Failed to get signing certificate object.");
                    }
                else {
                    System.out.println("Signing cert: " + cert.subjectCN());

                    }

                }
            else {
                System.out.println("Digital signature verification failed.");
                }

            }

        i = i+1;
        }

    mailman.Pop3EndSession();
  }
}