libsaltpack-jni

A Java Native Interface wrapper for libsaltpack.

Dependencies

• libsaltpack
• libsodium >= 1.0.9
• msgpack >= 2.0.0

libsodium should be compiled with PIC enabled (./configure --with-pic).

Building

Here's how to build the JAR package and the dynamic library on Linux or OSX:

mvn compile
cmake .
make
mvn exec:java -Dexec.mainClass="com.gherynos.libsaltpack.Loader"
mvn package

Android

Here's how to build libsaltpack-jni and all its dependencies for Android using Docker:

docker run --platform=linux/amd64 --rm -v `pwd`:/opt/libsaltpack-jni -t ubuntu:jammy /bin/bash /opt/libsaltpack-jni/android/compile.sh

This will produce the libsaltpack-jni-<version>.jar file under the target directory, containing the Java classes and the binary libraries.

Documentation

The Javadoc can be found here: https://libsaltpack-jni.gherynos.com.

Examples

Encrypt/decrypt message

import com.gherynos.libsaltpack.*;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

class Test {

    public static void main(String[] args) {

        try {

            // generate keypair
            byte[] publickey = new byte[Constants.CRYPTO_BOX_PUBLICKEYBYTES];
            byte[] secretkey = new byte[Constants.CRYPTO_BOX_SECRETKEYBYTES];
            Utils.generateKeypair(publickey, secretkey);

            // recipients
            byte[][] recipients = {publickey};

            // encrypt message
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            OutputParameters op = new OutputParameters(out);
            op.setArmored(true);
            MessageWriter enc = new MessageWriter(op, secretkey, recipients);
            enc.addBlock(new byte[]{'T', 'h', 'e', ' ', 'm', 'e', 's', 's', 'a', 'g', 'e'}, false);
            enc.addBlock(new byte[]{' ', ':', ')'}, true);

            out.flush();
            enc.destroy();

            // display encrypted message
            System.out.println(new String(out.toByteArray(), "UTF-8"));

            // decrypt message
            ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
            InputParameters ip = new InputParameters(in);
            ip.setArmored(true);
            StringBuilder msg = new StringBuilder();
            MessageReader dec = new MessageReader(ip, secretkey);
            while (dec.hasMoreBlocks())
                msg.append(new String(dec.getBlock(), "UTF-8"));
            dec.destroy();

            // display decrypted message
            System.out.println(msg.toString());

        } catch (SaltpackException | IOException ex) {

            System.err.println(ex.getMessage());
        }
    }
}

Sign/verify message

Attached signature

import com.gherynos.libsaltpack.*;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

class Test {

    public static void main(String[] args) {

        try {

            // generate keypair
            byte[] publickey = new byte[Constants.CRYPTO_SIGN_PUBLICKEYBYTES];
            byte[] secretkey = new byte[Constants.CRYPTO_SIGN_SECRETKEYBYTES];
            Utils.generateSignKeypair(publickey, secretkey);

            // sign message
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            OutputParameters op = new OutputParameters(out);
            op.setArmored(true);
            MessageWriter enc = new MessageWriter(op, secretkey, false);
            enc.addBlock(new byte[]{'a', ' ', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'm', 's', 'g'}, true);

            out.flush();
            enc.destroy();

            // display signed message
            System.out.println(new String(out.toByteArray(), "UTF-8"));

            // verify message
            ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
            InputParameters ip = new InputParameters(in);
            ip.setArmored(true);
            StringBuilder msg = new StringBuilder();
            MessageReader dec = new MessageReader(ip);
            while (dec.hasMoreBlocks())
                msg.append(new String(dec.getBlock(), "UTF-8"));
            dec.destroy();

            // display verified message
            System.out.println(msg.toString());

        } catch (SaltpackException | IOException ex) {

            System.err.println(ex.getMessage());
        }
    }
}

Detached signature

import com.gherynos.libsaltpack.*;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

class Test {

    public static void main(String[] args) {

        try {

            // generate keypair
            byte[] publickey = new byte[Constants.CRYPTO_SIGN_PUBLICKEYBYTES];
            byte[] secretkey = new byte[Constants.CRYPTO_SIGN_SECRETKEYBYTES];
            Utils.generateSignKeypair(publickey, secretkey);

            // sign message
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            OutputParameters op = new OutputParameters(out);
            op.setArmored(true);
            MessageWriter enc = new MessageWriter(op, secretkey, true);
            enc.addBlock(new byte[]{'a', ' ', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'm', 's', 'g'}, true);

            out.flush();
            enc.destroy();

            // display signature
            System.out.println(new String(out.toByteArray(), "UTF-8"));

            // verify message
            ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
            InputParameters ip = new InputParameters(in);
            ip.setArmored(true);
            ByteArrayInputStream msg = new ByteArrayInputStream("a signed msg".getBytes());
            MessageReader dec = new MessageReader(ip, msg);
            dec.destroy();

        } catch (SaltpackException | IOException ex) {

            System.err.println(ex.getMessage());
        }
    }
}

Signcrypt message

Curve25519 key

import com.gherynos.libsaltpack.*;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

class Test {

    public static void main(String[] args) {

        try {

            // generate signer keypair
            byte[] secretkey = new byte[Constants.CRYPTO_SIGN_SECRETKEYBYTES];
            byte[] publickey = new byte[Constants.CRYPTO_SIGN_PUBLICKEYBYTES];
            Utils.generateSignKeypair(publickey, secretkey);

            // generate recipient keypair
            byte[] recipientPublickey = new byte[Constants.CRYPTO_BOX_PUBLICKEYBYTES];
            byte[] recipientSecretkey = new byte[Constants.CRYPTO_BOX_SECRETKEYBYTES];
            Utils.generateKeypair(recipientPublickey, recipientSecretkey);

            // asymmetric keys
            byte[][] recipients = {recipientPublickey};

            // symmetric keys (empty)
            byte[][][] symmetricKeys = {};

            // signcrypt message
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            OutputParameters op = new OutputParameters(out);
            op.setArmored(true);
            MessageWriter enc = new MessageWriter(op, secretkey, recipients, symmetricKeys);
            enc.addBlock(new byte[]{'T', 'h', 'e', ' ', 'm', 'e', 's', 's', 'a', 'g', 'e'}, false);
            enc.addBlock(new byte[]{' ', ':', ')'}, true);

            out.flush();
            enc.destroy();

            // display signcrypted message
            System.out.println(new String(out.toByteArray(), "UTF-8"));

            // verify message
            ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
            InputParameters ip = new InputParameters(in);
            ip.setArmored(true);
            StringBuilder msg = new StringBuilder();
            MessageReader dec = new MessageReader(ip, recipientSecretkey, new byte[][]{});
            while (dec.hasMoreBlocks())
                msg.append(new String(dec.getBlock(), "UTF-8"));
            dec.destroy();

            // display decrypted message
            System.out.println(msg.toString());

        } catch (SaltpackException | IOException ex) {

            System.err.println(ex.getMessage());
        }
    }
}

Symmetric key

import com.gherynos.libsaltpack.*;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

class Test {

    public static void main(String[] args) {

        try {

            // generate signer keypair
            byte[] secretkey = new byte[Constants.CRYPTO_SIGN_SECRETKEYBYTES];
            byte[] publickey = new byte[Constants.CRYPTO_SIGN_PUBLICKEYBYTES];
            Utils.generateSignKeypair(publickey, secretkey);

            // asymmetric keys (empty)
            byte[][] recipients = {};

            // symmetric keys
            byte[][] key = {
                    Utils.generateRandomBytes(32),
                    Utils.generateRandomBytes(Constants.CRYPTO_SECRETBOX_KEYBYTES)};
            byte[][][] symmetricKeys = {key};

            // signcrypt message
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            OutputParameters op = new OutputParameters(out);
            op.setArmored(true);
            MessageWriter enc = new MessageWriter(op, secretkey, recipients, symmetricKeys);
            enc.addBlock(new byte[]{'T', 'h', 'e', ' ', 'm', 'e', 's', 's', 'a', 'g', 'e'}, false);
            enc.addBlock(new byte[]{' ', ':', 'D'}, true);

            out.flush();
            enc.destroy();

            // display signcrypted message
            System.out.println(new String(out.toByteArray(), "UTF-8"));

            // verify message
            ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
            InputParameters ip = new InputParameters(in);
            ip.setArmored(true);
            StringBuilder msg = new StringBuilder();
            MessageReader dec = new MessageReader(ip, new byte[]{}, key);
            while (dec.hasMoreBlocks())
                msg.append(new String(dec.getBlock(), "UTF-8"));
            dec.destroy();

            // display decrypted message
            System.out.println(msg.toString());

        } catch (SaltpackException | IOException ex) {

            System.err.println(ex.getMessage());
        }
    }
}

Author

GitHub @gherynos

License

libsaltpack-jni is licensed under the Apache License, Version 2.0.