/*
* Copyright (c) [2016] [ <ether.camp> ]
* This file is part of the ethereumJ library.
*
* The ethereumJ library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* The ethereumJ library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the ethereumJ library. If not, see <http://www.gnu.org/licenses/>.
*/
package org.ethereum.crypto.jce;
import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.InvalidAlgorithmParameterException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Provider;
import java.security.SecureRandom;
import java.security.spec.ECGenParameterSpec;
public final class ECKeyPairGenerator {
public static final String ALGORITHM = "EC";
public static final String CURVE_NAME = "secp256k1";
private static final String algorithmAssertionMsg =
"Assumed JRE supports EC key pair generation";
private static final String keySpecAssertionMsg =
"Assumed correct key spec statically";
private static final ECGenParameterSpec SECP256K1_CURVE
= new ECGenParameterSpec(CURVE_NAME);
private ECKeyPairGenerator() { }
private static class Holder {
private static final KeyPairGenerator INSTANCE;
static {
try {
INSTANCE = KeyPairGenerator.getInstance(ALGORITHM);
INSTANCE.initialize(SECP256K1_CURVE);
} catch (NoSuchAlgorithmException ex) {
throw new AssertionError(algorithmAssertionMsg, ex);
} catch (InvalidAlgorithmParameterException ex) {
throw new AssertionError(keySpecAssertionMsg, ex);
}
}
}
public static KeyPair generateKeyPair() {
return Holder.INSTANCE.generateKeyPair();
}
public static KeyPairGenerator getInstance(final String provider, final SecureRandom random) throws NoSuchProviderException {
try {
final KeyPairGenerator gen = KeyPairGenerator.getInstance(ALGORITHM, provider);
gen.initialize(SECP256K1_CURVE, random);
return gen;
} catch (NoSuchAlgorithmException ex) {
throw new AssertionError(algorithmAssertionMsg, ex);
} catch (InvalidAlgorithmParameterException ex) {
throw new AssertionError(keySpecAssertionMsg, ex);
}
}
public static KeyPairGenerator getInstance(final Provider provider, final SecureRandom random) {
try {
final KeyPairGenerator gen = KeyPairGenerator.getInstance(ALGORITHM, provider);
gen.initialize(SECP256K1_CURVE, random);
return gen;
} catch (NoSuchAlgorithmException ex) {
throw new AssertionError(algorithmAssertionMsg, ex);
} catch (InvalidAlgorithmParameterException ex) {
throw new AssertionError(keySpecAssertionMsg, ex);
}
}
}