org.bouncycastle.pqc.jcajce.provider.newhope.KeyAgreementSpi Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of bcprov-ext-debug-jdk18on Show documentation

The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for Java 1.8 and later with debug enabled.

The newest version!

package org.bouncycastle.pqc.jcajce.provider.newhope;

import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.ShortBufferException;

import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
import org.bouncycastle.jcajce.provider.asymmetric.util.BaseAgreementSpi;
import org.bouncycastle.pqc.crypto.ExchangePair;
import org.bouncycastle.pqc.crypto.newhope.NHAgreement;
import org.bouncycastle.pqc.crypto.newhope.NHExchangePairGenerator;
import org.bouncycastle.pqc.crypto.newhope.NHPublicKeyParameters;
import org.bouncycastle.util.Arrays;

public class KeyAgreementSpi
    extends BaseAgreementSpi
{
    private NHAgreement agreement;
    private BCNHPublicKey otherPartyKey;
    private NHExchangePairGenerator exchangePairGenerator;

    private byte[] shared;

    public KeyAgreementSpi()
    {
        super("NH", null);
    }

    protected void engineInit(Key key, SecureRandom secureRandom)
        throws InvalidKeyException
    {
        if (key != null)
        {
            agreement = new NHAgreement();

            agreement.init(((BCNHPrivateKey)key).getKeyParams());
        }
        else
        {
            exchangePairGenerator = new NHExchangePairGenerator(secureRandom);
        }
    }

    protected void doInitFromKey(Key key, AlgorithmParameterSpec algorithmParameterSpec, SecureRandom secureRandom)
        throws InvalidKeyException, InvalidAlgorithmParameterException
    {
        throw new InvalidAlgorithmParameterException("NewHope does not require parameters");
    }

    protected Key engineDoPhase(Key key, boolean lastPhase)
        throws InvalidKeyException, IllegalStateException
    {
        if (!lastPhase)
        {
            throw new IllegalStateException("NewHope can only be between two parties.");
        }

        otherPartyKey = (BCNHPublicKey)key;

        if (exchangePairGenerator != null)
        {
            ExchangePair exchPair = exchangePairGenerator.generateExchange((AsymmetricKeyParameter)otherPartyKey.getKeyParams());

            shared = exchPair.getSharedValue();

            return new BCNHPublicKey((NHPublicKeyParameters)exchPair.getPublicKey());
        }
        else
        {
            shared = agreement.calculateAgreement(otherPartyKey.getKeyParams());

            return null;
        }
    }

    protected byte[] engineGenerateSecret()
        throws IllegalStateException
    {
        byte[] rv = Arrays.clone(shared);

        Arrays.fill(shared, (byte)0);

        return rv;
    }

    protected int engineGenerateSecret(byte[] bytes, int offset)
        throws IllegalStateException, ShortBufferException
    {
        System.arraycopy(shared, 0, bytes, offset, shared.length);

        Arrays.fill(shared, (byte)0);

        return shared.length;
    }

    protected byte[] doCalcSecret()
    {
        return engineGenerateSecret();
    }
}