Java

Add a Detached Signature (Separate Key, Header Control)

Demonstrates the Chilkat Mime.AddDetachedSignaturePk2 method, which creates a detached signature with a separately supplied certificate and private key, and a third argument controlling transfer of the existing message header fields to the new outer entity.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This combines the two variations — certificate and key supplied separately, plus explicit header placement — for the case that needs both. It is the most flexible of the detached-signature methods; choose it when your key material is separate and you also care about where the message headers end up on the signed result.

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import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Mime;
import com.chilkatsoft.chilkat2.PrivateKey;

public class ChilkatExample {

    public static void main(String[] args) {
        Mime mime = new Mime();
        try {
            mime.setBodyFromPlainText("This message will be signed.");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Load the certificate and its private key separately.
        Cert cert = new Cert();
        try {
            cert.loadFromFile("qa_data/signer.cer");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        PrivateKey privKey = new PrivateKey();
        try {
            privKey.loadPemFile("qa_data/signer_privkey.pem");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Create a detached signature with separately supplied cert and private key, where the 3rd
        // argument controls whether the existing message header fields are transferred to the new outer
        // multipart/signed entity.
        boolean transferHeaderFields = true;
        try {
            mime.addDetachedSignaturePk2(cert, privKey, transferHeaderFields);

            mime.saveMime("qa_output/signed.eml");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Detached signature added (headers transferred).");
    }
}