org.bitcoinj.crypto.BLSKeyExchangeCrypter Maven / Gradle / Ivy
/*
* Copyright 2019 Dash Core Group
*
* Licensed under the MIT license (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://opensource.org/licenses/mit-license.php
*
* 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.bitcoinj.crypto;
import com.google.common.base.Stopwatch;
import org.bitcoinj.core.Utils;
import org.bitcoinj.wallet.Protos.Wallet.EncryptionType;
import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.engines.AESEngine;
import org.bouncycastle.crypto.modes.CBCBlockCipher;
import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;
import org.dashj.bls.BLS;
import org.dashj.bls.PublicKey;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.security.SecureRandom;
import java.util.Arrays;
import static com.google.common.base.Preconditions.checkNotNull;
/**
* This class encrypts and decrypts byte arrays and strings using a BLS Key Exchange as the
* key derivation function and AES for the encryption.
*
* You can use this class to:
*
* 1) Using a BLS private key and a public key, create an AES key that can encrypt and decrypt data.
*
*
* 2) Using the AES Key generated above, you then can encrypt and decrypt any bytes using
* the AES symmetric cipher. Eight bytes of salt is used to prevent dictionary attacks.
*/
public class BLSKeyExchangeCrypter extends KeyCrypterAESCBC {
private static final Logger log = LoggerFactory.getLogger(BLSKeyExchangeCrypter.class);
/**
* Generate AES key.
*
* This is a very slow operation compared to encrypt/ decrypt so it is normally worth caching the result.
*
* @param password The password to use in key generation
* @return The KeyParameter containing the created AES key
* @throws KeyCrypterException
*/
@Override
public KeyParameter deriveKey(CharSequence password) throws KeyCrypterException {
throw new UnsupportedOperationException("use deriveKey(BLSSecretKey, BLSPublicKey) instead");
}
public KeyParameter deriveKey(BLSSecretKey secretKey, BLSPublicKey blsPeerPublicKey) throws KeyCrypterException {
try {
final Stopwatch watch = Stopwatch.createStarted();
PublicKey pk = BLS.DHKeyExchange(secretKey.privateKey, blsPeerPublicKey.publicKeyImpl);
watch.stop();
byte [] key = new byte [32];
System.arraycopy(pk.Serialize(), 0, key, 0, 32);
log.info("Deriving key took {} for a BLS Key Exchange", watch);
return new KeyParameter(key);
} catch (Exception e) {
throw new KeyCrypterException("Could not generate key from BLS private and public keys.", e);
}
}
/**
* Return the EncryptionType enum value which denotes the type of encryption/ decryption that this KeyCrypter
* can understand.
*/
@Override
public EncryptionType getUnderstoodEncryptionType() {
return EncryptionType.ENCRYPTED_BLS_KEYEXCHANGE_AES;
}
@Override
public String toString() {
return "AES-" + KEY_LENGTH * 8 + "-CBC, BLS DHExchangeKey)";
}
}