org.bouncycastle.pqc.crypto.ntru.NTRUKeyPairGenerator Maven / Gradle / Ivy
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package org.bouncycastle.pqc.crypto.ntru;
import java.security.SecureRandom;
import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
import org.bouncycastle.crypto.AsymmetricCipherKeyPairGenerator;
import org.bouncycastle.crypto.KeyGenerationParameters;
import org.bouncycastle.pqc.math.ntru.parameters.NTRUParameterSet;
/**
* Key generator for NTRU.
*
* Note: the {@link #init(KeyGenerationParameters)} method only accepts {@link NTRUKeyParameters}. Otherwise, a
* {@link ClassCastException} may occur.
*/
public class NTRUKeyPairGenerator
implements AsymmetricCipherKeyPairGenerator
{
private NTRUKeyGenerationParameters params;
private SecureRandom random;
@Override
public void init(KeyGenerationParameters param)
{
this.params = (NTRUKeyGenerationParameters)param;
this.random = param.getRandom();
}
@Override
public AsymmetricCipherKeyPair generateKeyPair()
{
// assert this.random != null;
NTRUParameterSet parameterSet = this.params.getParameters().parameterSet;
byte[] seed = new byte[parameterSet.sampleFgBytes()];
random.nextBytes(seed);
NTRUOWCPA owcpa = new NTRUOWCPA(parameterSet);
OWCPAKeyPair owcpaKeys = owcpa.keypair(seed);
byte[] publicKey = owcpaKeys.publicKey;
byte[] privateKey = new byte[parameterSet.ntruSecretKeyBytes()];
byte[] owcpaPrivateKey = owcpaKeys.privateKey;
System.arraycopy(owcpaPrivateKey, 0, privateKey, 0, owcpaPrivateKey.length);
byte[] prfBytes = new byte[parameterSet.prfKeyBytes()];
random.nextBytes(prfBytes);
System.arraycopy(prfBytes, 0, privateKey, parameterSet.owcpaSecretKeyBytes(), prfBytes.length);
return new AsymmetricCipherKeyPair(new NTRUPublicKeyParameters(params.getParameters(), publicKey), new NTRUPrivateKeyParameters(params.getParameters(), privateKey));
}
}