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Spongy Castle is a package-rename (org.bouncycastle.* to org.spongycastle.*) of Bouncy Castle intended for Android.
Android ships with a stripped-down version of Bouncy Castle - this causes classloader collisions if you try to add
an alternative (updated/complete) Bouncy Castle jar.
This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5.
package org.spongycastle.jce.provider;
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.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.MGF1ParameterSpec;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.interfaces.DHKey;
import javax.crypto.spec.OAEPParameterSpec;
import javax.crypto.spec.PSource;
import org.spongycastle.crypto.AsymmetricBlockCipher;
import org.spongycastle.crypto.BufferedAsymmetricBlockCipher;
import org.spongycastle.crypto.CipherParameters;
import org.spongycastle.crypto.Digest;
import org.spongycastle.crypto.InvalidCipherTextException;
import org.spongycastle.crypto.encodings.ISO9796d1Encoding;
import org.spongycastle.crypto.encodings.OAEPEncoding;
import org.spongycastle.crypto.encodings.PKCS1Encoding;
import org.spongycastle.crypto.engines.ElGamalEngine;
import org.spongycastle.crypto.params.ParametersWithRandom;
import org.spongycastle.jce.interfaces.ElGamalKey;
import org.spongycastle.jce.interfaces.ElGamalPrivateKey;
import org.spongycastle.jce.interfaces.ElGamalPublicKey;
import org.spongycastle.util.Strings;
public class JCEElGamalCipher extends WrapCipherSpi
{
private BufferedAsymmetricBlockCipher cipher;
private AlgorithmParameterSpec paramSpec;
private AlgorithmParameters engineParams;
public JCEElGamalCipher(
AsymmetricBlockCipher engine)
{
cipher = new BufferedAsymmetricBlockCipher(engine);
}
private void initFromSpec(
OAEPParameterSpec pSpec)
throws NoSuchPaddingException
{
MGF1ParameterSpec mgfParams = (MGF1ParameterSpec)pSpec.getMGFParameters();
Digest digest = JCEDigestUtil.getDigest(mgfParams.getDigestAlgorithm());
if (digest == null)
{
throw new NoSuchPaddingException("no match on OAEP constructor for digest algorithm: "+ mgfParams.getDigestAlgorithm());
}
cipher = new BufferedAsymmetricBlockCipher(new OAEPEncoding(new ElGamalEngine(), digest, ((PSource.PSpecified)pSpec.getPSource()).getValue()));
paramSpec = pSpec;
}
protected int engineGetBlockSize()
{
return cipher.getInputBlockSize();
}
protected byte[] engineGetIV()
{
return null;
}
protected int engineGetKeySize(
Key key)
{
if (key instanceof ElGamalKey)
{
ElGamalKey k = (ElGamalKey)key;
return k.getParameters().getP().bitLength();
}
else if (key instanceof DHKey)
{
DHKey k = (DHKey)key;
return k.getParams().getP().bitLength();
}
throw new IllegalArgumentException("not an ElGamal key!");
}
protected int engineGetOutputSize(
int inputLen)
{
return cipher.getOutputBlockSize();
}
protected AlgorithmParameters engineGetParameters()
{
if (engineParams == null)
{
if (paramSpec != null)
{
try
{
engineParams = AlgorithmParameters.getInstance("OAEP", BouncyCastleProvider.PROVIDER_NAME);
engineParams.init(paramSpec);
}
catch (Exception e)
{
throw new RuntimeException(e.toString());
}
}
}
return engineParams;
}
protected void engineSetMode(
String mode)
throws NoSuchAlgorithmException
{
String md = Strings.toUpperCase(mode);
if (md.equals("NONE") || md.equals("ECB"))
{
return;
}
throw new NoSuchAlgorithmException("can't support mode " + mode);
}
protected void engineSetPadding(
String padding)
throws NoSuchPaddingException
{
String pad = Strings.toUpperCase(padding);
if (pad.equals("NOPADDING"))
{
cipher = new BufferedAsymmetricBlockCipher(new ElGamalEngine());
}
else if (pad.equals("PKCS1PADDING"))
{
cipher = new BufferedAsymmetricBlockCipher(new PKCS1Encoding(new ElGamalEngine()));
}
else if (pad.equals("ISO9796-1PADDING"))
{
cipher = new BufferedAsymmetricBlockCipher(new ISO9796d1Encoding(new ElGamalEngine()));
}
else if (pad.equals("OAEPPADDING"))
{
initFromSpec(OAEPParameterSpec.DEFAULT);
}
else if (pad.equals("OAEPWITHMD5ANDMGF1PADDING"))
{
initFromSpec(new OAEPParameterSpec("MD5", "MGF1", new MGF1ParameterSpec("MD5"), PSource.PSpecified.DEFAULT));
}
else if (pad.equals("OAEPWITHSHA1ANDMGF1PADDING"))
{
initFromSpec(OAEPParameterSpec.DEFAULT);
}
else if (pad.equals("OAEPWITHSHA224ANDMGF1PADDING"))
{
initFromSpec(new OAEPParameterSpec("SHA-224", "MGF1", new MGF1ParameterSpec("SHA-224"), PSource.PSpecified.DEFAULT));
}
else if (pad.equals("OAEPWITHSHA256ANDMGF1PADDING"))
{
initFromSpec(new OAEPParameterSpec("SHA-256", "MGF1", MGF1ParameterSpec.SHA256, PSource.PSpecified.DEFAULT));
}
else if (pad.equals("OAEPWITHSHA384ANDMGF1PADDING"))
{
initFromSpec(new OAEPParameterSpec("SHA-384", "MGF1", MGF1ParameterSpec.SHA384, PSource.PSpecified.DEFAULT));
}
else if (pad.equals("OAEPWITHSHA512ANDMGF1PADDING"))
{
initFromSpec(new OAEPParameterSpec("SHA-512", "MGF1", MGF1ParameterSpec.SHA512, PSource.PSpecified.DEFAULT));
}
else
{
throw new NoSuchPaddingException(padding + " unavailable with ElGamal.");
}
}
protected void engineInit(
int opmode,
Key key,
AlgorithmParameterSpec params,
SecureRandom random)
throws InvalidKeyException
{
CipherParameters param;
if (params == null)
{
if (key instanceof ElGamalPublicKey)
{
param = ElGamalUtil.generatePublicKeyParameter((PublicKey)key);
}
else if (key instanceof ElGamalPrivateKey)
{
param = ElGamalUtil.generatePrivateKeyParameter((PrivateKey)key);
}
else
{
throw new InvalidKeyException("unknown key type passed to ElGamal");
}
}
else
{
throw new IllegalArgumentException("unknown parameter type.");
}
if (random != null)
{
param = new ParametersWithRandom(param, random);
}
switch (opmode)
{
case Cipher.ENCRYPT_MODE:
case Cipher.WRAP_MODE:
cipher.init(true, param);
break;
case Cipher.DECRYPT_MODE:
case Cipher.UNWRAP_MODE:
cipher.init(false, param);
break;
default:
throw new InvalidParameterException("unknown opmode " + opmode + " passed to ElGamal");
}
}
protected void engineInit(
int opmode,
Key key,
AlgorithmParameters params,
SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException
{
throw new InvalidAlgorithmParameterException("can't handle parameters in ElGamal");
}
protected void engineInit(
int opmode,
Key key,
SecureRandom random)
throws InvalidKeyException
{
engineInit(opmode, key, (AlgorithmParameterSpec)null, random);
}
protected byte[] engineUpdate(
byte[] input,
int inputOffset,
int inputLen)
{
cipher.processBytes(input, inputOffset, inputLen);
return null;
}
protected int engineUpdate(
byte[] input,
int inputOffset,
int inputLen,
byte[] output,
int outputOffset)
{
cipher.processBytes(input, inputOffset, inputLen);
return 0;
}
protected byte[] engineDoFinal(
byte[] input,
int inputOffset,
int inputLen)
throws IllegalBlockSizeException, BadPaddingException
{
cipher.processBytes(input, inputOffset, inputLen);
try
{
return cipher.doFinal();
}
catch (InvalidCipherTextException e)
{
throw new BadPaddingException(e.getMessage());
}
}
protected int engineDoFinal(
byte[] input,
int inputOffset,
int inputLen,
byte[] output,
int outputOffset)
throws IllegalBlockSizeException, BadPaddingException
{
byte[] out;
cipher.processBytes(input, inputOffset, inputLen);
try
{
out = cipher.doFinal();
}
catch (InvalidCipherTextException e)
{
throw new BadPaddingException(e.getMessage());
}
for (int i = 0; i != out.length; i++)
{
output[outputOffset + i] = out[i];
}
return out.length;
}
/**
* classes that inherit from us.
*/
static public class NoPadding
extends JCEElGamalCipher
{
public NoPadding()
{
super(new ElGamalEngine());
}
}
static public class PKCS1v1_5Padding
extends JCEElGamalCipher
{
public PKCS1v1_5Padding()
{
super(new PKCS1Encoding(new ElGamalEngine()));
}
}
}