MIME S/MIME Signing Algorithm Properties

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Demonstrates the properties that control S/MIME signing: SigningAlg (the RSA signature scheme, PKCS1-V1_5 or RSASSA-PSS), SigningHashAlg (the message-digest algorithm), Micalg and Protocol (the micalg and protocol parameters of a multipart/signed Content-Type), and UseXPkcs7 (whether historical x-pkcs7 media-type names are used). The properties are configured before creating a detached signature.

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

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;
        }

        // SigningAlg is the RSA signature scheme.  The default is PKCS1-V1_5; set RSASSA-PSS (or pss) for
        // RSASSA-PSS.
        mime.setSigningAlg("PKCS1-V1_5");

        // SigningHashAlg is the message-digest algorithm.  The default is sha256.
        mime.setSigningHashAlg("sha256");

        // Micalg and Protocol are the micalg and protocol parameters written into a multipart/signed
        // Content-Type header field.  They are normally set automatically, but can be controlled here.
        mime.setMicalg("sha-256");
        mime.setProtocol("application/pkcs7-signature");

        // UseXPkcs7 controls whether newly created S/MIME media types use the historical x-pkcs7 names.
        mime.setUseXPkcs7(false);

        // Load a signing certificate (with private key access) from a PFX.  The PFX password should come
        // from a secure source rather than being hard-coded.
        String pfxPassword = "myPfxPassword";
        Cert cert = new Cert();
        try {
            cert.loadPfxFile("qa_data/signer.pfx", pfxPassword);

            // Create the detached signature using the algorithms configured above.
            mime.addDetachedSignature(cert);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Signed with SigningAlg=" + mime.getSigningAlg() + " SigningHashAlg=" + mime.getSigningHashAlg());
    }
}