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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 JDK 1.5 to JDK 1.8.
package org.bouncycastle.pqc.jcajce.provider.ntru;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.InvalidParameterException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.CipherSpi;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.ShortBufferException;
import javax.crypto.spec.SecretKeySpec;
import javax.security.auth.DestroyFailedException;
import org.bouncycastle.crypto.CryptoServicesRegistrar;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.SecretWithEncapsulation;
import org.bouncycastle.crypto.Wrapper;
import org.bouncycastle.jcajce.spec.KEMParameterSpec;
import org.bouncycastle.jcajce.spec.KTSParameterSpec;
import org.bouncycastle.pqc.crypto.ntru.NTRUKEMExtractor;
import org.bouncycastle.pqc.crypto.ntru.NTRUKEMGenerator;
import org.bouncycastle.pqc.jcajce.provider.util.WrapUtil;
import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.Exceptions;
class NTRUCipherSpi
extends CipherSpi
{
private final String algorithmName;
private NTRUKEMGenerator kemGen;
private KTSParameterSpec kemParameterSpec;
private BCNTRUPublicKey wrapKey;
private BCNTRUPrivateKey unwrapKey;
private AlgorithmParameters engineParams;
NTRUCipherSpi(String algorithmName)
throws NoSuchAlgorithmException
{
this.algorithmName = algorithmName;
}
@Override
protected void engineSetMode(String mode)
throws NoSuchAlgorithmException
{
throw new NoSuchAlgorithmException("Cannot support mode " + mode);
}
@Override
protected void engineSetPadding(String padding)
throws NoSuchPaddingException
{
throw new NoSuchPaddingException("Padding " + padding + " unknown");
}
protected int engineGetKeySize(
Key key)
{
return 2048; // TODO
//throw new IllegalArgumentException("not an valid key!");
}
@Override
protected int engineGetBlockSize()
{
return 0;
}
@Override
protected int engineGetOutputSize(int i)
{
return -1; // can't use with update/doFinal
}
@Override
protected byte[] engineGetIV()
{
return null;
}
@Override
protected AlgorithmParameters engineGetParameters()
{
if (engineParams == null)
{
try
{
engineParams = AlgorithmParameters.getInstance(algorithmName, "BCPQC");
engineParams.init(kemParameterSpec);
}
catch (Exception e)
{
throw Exceptions.illegalStateException(e.toString(), e);
}
}
return engineParams;
}
@Override
protected void engineInit(int opmode, Key key, SecureRandom random)
throws InvalidKeyException
{
try
{
engineInit(opmode, key, (AlgorithmParameterSpec)null, random);
}
catch (InvalidAlgorithmParameterException e)
{
throw Exceptions.illegalArgumentException(e.getMessage(), e);
}
}
@Override
protected void engineInit(int opmode, Key key, AlgorithmParameterSpec paramSpec, SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException
{
if (paramSpec == null)
{
// TODO: default should probably use shake.
kemParameterSpec = new KEMParameterSpec("AES-KWP");
}
else
{
if (!(paramSpec instanceof KTSParameterSpec))
{
throw new InvalidAlgorithmParameterException(algorithmName + " can only accept KTSParameterSpec");
}
kemParameterSpec = (KTSParameterSpec)paramSpec;
}
if (opmode == Cipher.WRAP_MODE)
{
if (key instanceof BCNTRUPublicKey)
{
wrapKey = (BCNTRUPublicKey)key;
kemGen = new NTRUKEMGenerator(CryptoServicesRegistrar.getSecureRandom(random));
}
else
{
throw new InvalidKeyException("Only a " + algorithmName + " public key can be used for wrapping");
}
}
else if (opmode == Cipher.UNWRAP_MODE)
{
if (key instanceof BCNTRUPrivateKey)
{
unwrapKey = (BCNTRUPrivateKey)key;
}
else
{
throw new InvalidKeyException("Only a " + algorithmName + " private key can be used for unwrapping");
}
}
else
{
throw new InvalidParameterException("Cipher only valid for wrapping/unwrapping");
}
}
@Override
protected void engineInit(int opmode, Key key, AlgorithmParameters algorithmParameters, SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException
{
AlgorithmParameterSpec paramSpec = null;
if (algorithmParameters != null)
{
try
{
paramSpec = algorithmParameters.getParameterSpec(KEMParameterSpec.class);
}
catch (Exception e)
{
throw new InvalidAlgorithmParameterException("can't handle parameter " + algorithmParameters.toString());
}
}
engineInit(opmode, key, paramSpec, random);
}
@Override
protected byte[] engineUpdate(byte[] bytes, int i, int i1)
{
throw new IllegalStateException("Not supported in a wrapping mode");
}
@Override
protected int engineUpdate(byte[] bytes, int i, int i1, byte[] bytes1, int i2)
throws ShortBufferException
{
throw new IllegalStateException("Not supported in a wrapping mode");
}
@Override
protected byte[] engineDoFinal(byte[] bytes, int i, int i1)
throws IllegalBlockSizeException, BadPaddingException
{
throw new IllegalStateException("Not supported in a wrapping mode");
}
@Override
protected int engineDoFinal(byte[] bytes, int i, int i1, byte[] bytes1, int i2)
throws ShortBufferException, IllegalBlockSizeException, BadPaddingException
{
throw new IllegalStateException("Not supported in a wrapping mode");
}
protected byte[] engineWrap(
Key key)
throws IllegalBlockSizeException, InvalidKeyException
{
byte[] encoded = key.getEncoded();
if (encoded == null)
{
throw new InvalidKeyException("Cannot wrap key, null encoding.");
}
try
{
SecretWithEncapsulation secEnc = kemGen.generateEncapsulated(wrapKey.getKeyParams());
Wrapper kWrap = WrapUtil.getKeyWrapper(kemParameterSpec, secEnc.getSecret());
byte[] encapsulation = secEnc.getEncapsulation();
secEnc.destroy();
byte[] keyToWrap = key.getEncoded();
byte[] rv = Arrays.concatenate(encapsulation, kWrap.wrap(keyToWrap, 0, keyToWrap.length));
Arrays.clear(keyToWrap);
return rv;
}
catch (IllegalArgumentException e)
{
throw new IllegalBlockSizeException("unable to generate KTS secret: " + e.getMessage());
}
catch (DestroyFailedException e)
{
throw new IllegalBlockSizeException("unable to destroy interim values: " + e.getMessage());
}
}
protected Key engineUnwrap(
byte[] wrappedKey,
String wrappedKeyAlgorithm,
int wrappedKeyType)
throws InvalidKeyException, NoSuchAlgorithmException
{
// TODO: add support for other types.
if (wrappedKeyType != Cipher.SECRET_KEY)
{
throw new InvalidKeyException("only SECRET_KEY supported");
}
try
{
NTRUKEMExtractor kemExt = new NTRUKEMExtractor(unwrapKey.getKeyParams());
byte[] secret = kemExt.extractSecret(Arrays.copyOfRange(wrappedKey, 0, kemExt.getEncapsulationLength()));
Wrapper kWrap = WrapUtil.getKeyUnwrapper(kemParameterSpec, secret);
Arrays.clear(secret);
byte[] keyEncBytes = Arrays.copyOfRange(wrappedKey, kemExt.getEncapsulationLength(), wrappedKey.length);
SecretKey rv = new SecretKeySpec(kWrap.unwrap(keyEncBytes, 0, keyEncBytes.length), wrappedKeyAlgorithm);
return rv;
}
catch (IllegalArgumentException e)
{
throw new NoSuchAlgorithmException("unable to extract KTS secret: " + e.getMessage());
}
catch (InvalidCipherTextException e)
{
throw new InvalidKeyException("unable to extract KTS secret: " + e.getMessage());
}
}
public static class Base
extends NTRUCipherSpi
{
public Base()
throws NoSuchAlgorithmException
{
super("NTRU");
}
}
}