Qfyilyi

I was wondering if there are already Providers in the Java Cryptography Architecture (JCA) for post-quantum signature schemes, especially XMSS^MT?

Here is an example taken almost verbatim from the Bouncycastle source code in org.bouncycastle.pqc.jcajce.provider.test.XMSSMTTest. This code was run on Java 8.

import org.bouncycastle.pqc.jcajce.interfaces.StateAwareSignature;

import org.bouncycastle.pqc.jcajce.provider.BouncyCastlePQCProvider;

import org.bouncycastle.pqc.jcajce.spec.XMSSMTParameterSpec;

import org.bouncycastle.util.Strings;



import java.security.*;



public class Main {



    private static void fail(boolean condition, String msg) {

        if (condition) {

            throw new RuntimeException(msg);

        }

    }



    public static void main(String args) throws Exception {

        Security.addProvider(new BouncyCastlePQCProvider());

        byte msg = Strings.toByteArray("Cthulhu Fthagn --What a wonderful phrase!Cthulhu Fthagn --Say it and you're crazed!");

        KeyPairGenerator kpg = KeyPairGenerator.getInstance("XMSSMT", "BCPQC");



        kpg.initialize(new XMSSMTParameterSpec(20, 10, XMSSMTParameterSpec.SHA256), new SecureRandom());



        KeyPair kp = kpg.generateKeyPair();



        Signature sig = Signature.getInstance("SHA256withXMSSMT", "BCPQC");



        fail(!(sig instanceof StateAwareSignature), "wrong signature instance");



        StateAwareSignature xmssSig = (StateAwareSignature) sig;



        xmssSig.initSign(kp.getPrivate());



        fail(!xmssSig.isSigningCapable(), "signature object is not signing-capable");



        xmssSig.update(msg, 0, msg.length);



        byte s = sig.sign();



        PrivateKey nKey = xmssSig.getUpdatedPrivateKey();



        fail(kp.getPrivate().equals(nKey), "");

        fail(xmssSig.isSigningCapable(), "signature object is signing-capable");



        xmssSig.update(msg, 0, msg.length);



        try {

            sig.sign();

            fail(true, "no exception after key extraction");

        } catch (SignatureException e) {

            fail(!"signing key no longer usable".equals(e.getMessage()), "wrong exception");

        }



        try {

            xmssSig.getUpdatedPrivateKey();

            fail(true, "no exception after key extraction");

        } catch (IllegalStateException e) {

            fail(!"signature object not in a signing state".equals(e.getMessage()), "wrong exception");

        }



        xmssSig.initSign(nKey);



        xmssSig.update(msg, 0, msg.length);



        s = sig.sign();



        xmssSig.initVerify(kp.getPublic());



        xmssSig.update(msg, 0, msg.length);



        fail(!xmssSig.verify(s), "verification failure");

    }

}

There are other examples in that file as well. Source code is available here.