/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.keyczar;
import com.google.gson.annotations.Expose;
import org.keyczar.enums.KeyType;
import org.keyczar.exceptions.KeyczarException;
import org.keyczar.interfaces.SigningStream;
import org.keyczar.interfaces.Stream;
import org.keyczar.interfaces.VerifyingStream;
import org.keyczar.util.Base64Coder;
import org.keyczar.util.Util;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Signature;
import java.security.SignatureException;
import java.security.interfaces.DSAPrivateKey;
import java.security.interfaces.DSAPublicKey;
import java.security.spec.DSAPrivateKeySpec;
/**
* Wrapping class for DSA Private Keys
*
* @author steveweis@gmail.com (Steve Weis)
* @author arkajit.dey@gmail.com (Arkajit Dey)
*
*/
class DsaPrivateKey extends KeyczarKey implements KeyczarPrivateKey {
private static final String KEY_GEN_ALGORITHM = "DSA";
private static final String SIG_ALGORITHM = "SHA1withDSA";
@Expose private DsaPublicKey publicKey;
@Expose private String x;
private DSAPrivateKey jcePrivateKey;
private DsaPrivateKey() {
publicKey = new DsaPublicKey();
}
@Override
byte[] hash() {
return getPublic().hash();
}
public String getKeyGenAlgorithm() {
return KEY_GEN_ALGORITHM;
}
public KeyczarPublicKey getPublic() {
return publicKey;
}
@Override
Stream getStream() throws KeyczarException {
return new DsaSigningStream();
}
@Override
KeyType getType() {
return KeyType.DSA_PRIV;
}
public void setPublic(KeyczarPublicKey pub) throws KeyczarException {
publicKey = (DsaPublicKey) pub;
publicKey.init();
}
static DsaPrivateKey generate() throws KeyczarException {
return generate(KeyType.DSA_PRIV.defaultSize());
}
void init() throws KeyczarException {
publicKey.init();
BigInteger xVal = new BigInteger(Base64Coder.decode(x));
BigInteger pVal = new BigInteger(Base64Coder.decode(publicKey.p));
BigInteger qVal = new BigInteger(Base64Coder.decode(publicKey.q));
BigInteger gVal = new BigInteger(Base64Coder.decode(publicKey.g));
DSAPrivateKeySpec spec = new DSAPrivateKeySpec(xVal, pVal, qVal, gVal);
try {
KeyFactory kf = KeyFactory.getInstance(KEY_GEN_ALGORITHM);
jcePrivateKey = (DSAPrivateKey) kf.generatePrivate(spec);
} catch (GeneralSecurityException e) {
throw new KeyczarException(e);
}
}
static DsaPrivateKey generate(int keySize) throws KeyczarException {
DsaPrivateKey key = new DsaPrivateKey();
KeyPairGenerator kpg;
try {
kpg = KeyPairGenerator.getInstance(KEY_GEN_ALGORITHM);
} catch (GeneralSecurityException e) {
throw new KeyczarException(e);
}
key.size = keySize;
kpg.initialize(key.size());
KeyPair pair = kpg.generateKeyPair();
key.jcePrivateKey = (DSAPrivateKey) pair.getPrivate();
DSAPublicKey pubKey = (DSAPublicKey) pair.getPublic();
key.publicKey.set(pubKey.getY(), pubKey.getParams().getP(),
pubKey.getParams().getQ(), pubKey.getParams().getG());
// Initialize the private key's JSON fields
key.x = Base64Coder.encode(key.jcePrivateKey.getX().toByteArray());
key.init();
return key;
}
static DsaPrivateKey read(String input) throws KeyczarException {
DsaPrivateKey key = Util.gson().fromJson(input, DsaPrivateKey.class);
key.init();
return key;
}
private class DsaSigningStream implements SigningStream, VerifyingStream {
private Signature signature;
private VerifyingStream verifyingStream;
public DsaSigningStream() throws KeyczarException {
try {
signature = Signature.getInstance(SIG_ALGORITHM);
verifyingStream = (VerifyingStream) publicKey.getStream();
} catch (GeneralSecurityException e) {
throw new KeyczarException(e);
}
}
public int digestSize() {
return getType().getOutputSize();
}
public void initSign() throws KeyczarException {
try {
signature.initSign(jcePrivateKey);
} catch (GeneralSecurityException e) {
throw new KeyczarException(e);
}
}
public void initVerify() throws KeyczarException {
verifyingStream.initVerify();
}
public void sign(ByteBuffer output) throws KeyczarException {
try {
byte[] sig = signature.sign();
output.put(sig);
} catch (SignatureException e) {
throw new KeyczarException(e);
}
}
public void updateSign(ByteBuffer input) throws KeyczarException {
try {
signature.update(input);
} catch (SignatureException e) {
throw new KeyczarException(e);
}
}
public void updateVerify(ByteBuffer input) throws KeyczarException {
verifyingStream.updateVerify(input);
}
public boolean verify(ByteBuffer sig) throws KeyczarException {
return verifyingStream.verify(sig);
}
}
}