javacryptographypost-quantum-cryptography

Is there already an XMSS/XMSS^MT Provider for Java JCA (Java Cryptography Architecture)?


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


Solution

  • 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.