Question

I’m now on developing digital signature app on android.

however, I failed to make a apk file because eclipse show following message

[2013-01-27 20:43:25 – BlowfishCipher] Dx
UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.IllegalArgumentException: already added: Lorg/bouncycastle/mozilla/SignedPublicKeyAndChallenge;

[2013-01-27 20:43:25 – BlowfishCipher] Dx at com.android.dx.dex.file.ClassDefsSection.add(ClassDefsSection.java:123)
[2013-01-27 20:43:25 – BlowfishCipher] Dx at com.android.dx.dex.file.DexFile.add(DexFile.java:163)

I know that the error message indicates that duplicated jar files but I don’t know how to
solve it since the duplicated jar (Lorg/bouncycastle/mozilla/SignedPublicKeyAndChallenge;) is the core file of the bouncy caslte library.

and follwing java code shows no syntax error but it cause java.lang.IllegalArgumentException: already added exception

package exam.blowfishcipher;

import java.io.FileWriter;
import java.io.OutputStreamWriter;
import java.security.KeyPair;
import java.security.SecureRandom;
import javax.security.auth.x500.X500Principal;
import org.bouncycastle.jce.PKCS10CertificationRequest;
import org.bouncycastle.openssl.PEMWriter;
import android.os.Environment;
import chapter6.PKCS10ExtensionExample;



public class PKCS10Generater
{
    public static PKCS10CertificationRequest generateRequest(
            KeyPair pair)
            throws Exception

            {           
             return new PKCS10CertificationRequest(
                     "SHA256withRSA",
                     new X500Principal("CN=Test CA Certificate"),
                     //new X500Principal("CN=end"),
                     pair.getPublic(),
                     null,
                     pair.getPrivate());
            }

    public static void pemEncodeToFile(String filename, Object obj, char[] password)     throws Exception{
        PEMWriter pw = new PEMWriter(new FileWriter(filename));
           if (password != null && password.length > 0) {
               pw.writeObject(obj, "DESEDE", password, new SecureRandom());
           } else {
               pw.writeObject(obj);
           }
           pw.flush();
           pw.close();
    }

    public static void reqGen() throws Exception
    {
        //create the keys
        /*
        KeyPairGenerator kpGen = KeyPairGenerator.getInstance("RSA", "BC");
        //KeyPairGenerator kpGen = KeyPairGenerator.getInstance()

        kpGen.initialize(512, chapter4.Utils.createFixedRandom());

        KeyPair pair=kpGen.generateKeyPair();
        */
        //PKCS10CertificationRequest request = generateRequest(pair);

        KeyPair pair = chapter8.Utils.generateRSAKeyPair();
        PKCS10CertificationRequest request = PKCS    10ExtensionExample.generateRequest(pair);


        pemEncodeToFile(Environment.getExternalStorageDirectory()+"pkcs10.req",     request, null);
        PEMWriter pemWrt = new PEMWriter( new OutputStreamWriter(System.out));
        pemWrt.writeObject(request);
        pemWrt.close();     
    }


}

Answer 1

Android already includes BouncyCastle in the system, that is why you are getting the error when trying to add it again (on recent versions it is actually in com.android.org.bouncycastle or some such so you shouldn’t get the error, in theory). You have to rename the package of BC if you want to include it in your project (with jarjar, etc.). One project that already does this for you is SpongyCastle. Try using that instead of the regular BC jar.

https://github.com/rtyley/spongycastle