156 lines
5.9 KiB
Java
156 lines
5.9 KiB
Java
/*
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* Copyright 2015 Christian Basler
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package ch.dissem.bitmessage.cryptography.sc;
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import ch.dissem.bitmessage.entity.payload.Pubkey;
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import ch.dissem.bitmessage.entity.valueobject.PrivateKey;
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import ch.dissem.bitmessage.exception.ApplicationException;
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import ch.dissem.bitmessage.ports.AbstractCryptography;
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import org.spongycastle.asn1.x9.X9ECParameters;
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import org.spongycastle.crypto.BufferedBlockCipher;
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import org.spongycastle.crypto.CipherParameters;
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import org.spongycastle.crypto.InvalidCipherTextException;
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import org.spongycastle.crypto.ec.CustomNamedCurves;
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import org.spongycastle.crypto.engines.AESEngine;
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import org.spongycastle.crypto.modes.CBCBlockCipher;
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import org.spongycastle.crypto.paddings.PKCS7Padding;
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import org.spongycastle.crypto.paddings.PaddedBufferedBlockCipher;
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import org.spongycastle.crypto.params.KeyParameter;
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import org.spongycastle.crypto.params.ParametersWithIV;
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import org.spongycastle.jce.provider.BouncyCastleProvider;
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import org.spongycastle.jce.spec.ECParameterSpec;
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import org.spongycastle.jce.spec.ECPrivateKeySpec;
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import org.spongycastle.jce.spec.ECPublicKeySpec;
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import org.spongycastle.math.ec.ECPoint;
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import java.math.BigInteger;
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import java.security.GeneralSecurityException;
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import java.security.KeyFactory;
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import java.security.PublicKey;
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import java.security.Signature;
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import java.security.spec.KeySpec;
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import java.util.Arrays;
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/**
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* As Spongycastle can't be used on the Oracle JVM, and Bouncycastle doesn't work properly on Android (thanks, Google),
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* this is the Spongycastle implementation.
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*/
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public class SpongyCryptography extends AbstractCryptography {
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private static final X9ECParameters EC_CURVE_PARAMETERS = CustomNamedCurves.getByName("secp256k1");
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private static final String ALGORITHM_ECDSA = "ECDSA";
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public SpongyCryptography() {
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super(new BouncyCastleProvider());
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}
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@Override
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public byte[] crypt(boolean encrypt, byte[] data, byte[] key_e, byte[] initializationVector) {
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BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(
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new CBCBlockCipher(new AESEngine()),
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new PKCS7Padding()
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);
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CipherParameters params = new ParametersWithIV(new KeyParameter(key_e), initializationVector);
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cipher.init(encrypt, params);
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byte[] buffer = new byte[cipher.getOutputSize(data.length)];
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int length = cipher.processBytes(data, 0, data.length, buffer, 0);
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try {
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length += cipher.doFinal(buffer, length);
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} catch (InvalidCipherTextException e) {
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throw new IllegalArgumentException(e);
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}
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if (length < buffer.length) {
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return Arrays.copyOfRange(buffer, 0, length);
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}
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return buffer;
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}
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@Override
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public byte[] createPublicKey(byte[] privateKey) {
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return EC_CURVE_PARAMETERS.getG().multiply(keyToBigInt(privateKey)).normalize().getEncoded(false);
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}
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private ECPoint keyToPoint(byte[] publicKey) {
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BigInteger x = new BigInteger(1, Arrays.copyOfRange(publicKey, 1, 33));
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BigInteger y = new BigInteger(1, Arrays.copyOfRange(publicKey, 33, 65));
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return EC_CURVE_PARAMETERS.getCurve().createPoint(x, y);
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}
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@Override
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public boolean isSignatureValid(byte[] data, byte[] signature, Pubkey pubkey) {
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try {
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ECParameterSpec spec = new ECParameterSpec(
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EC_CURVE_PARAMETERS.getCurve(),
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EC_CURVE_PARAMETERS.getG(),
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EC_CURVE_PARAMETERS.getN(),
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EC_CURVE_PARAMETERS.getH(),
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EC_CURVE_PARAMETERS.getSeed()
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);
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ECPoint Q = keyToPoint(pubkey.getSigningKey());
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KeySpec keySpec = new ECPublicKeySpec(Q, spec);
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PublicKey publicKey = KeyFactory.getInstance(ALGORITHM_ECDSA, provider).generatePublic(keySpec);
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Signature sig = Signature.getInstance(ALGORITHM_ECDSA, provider);
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sig.initVerify(publicKey);
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sig.update(data);
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return sig.verify(signature);
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} catch (GeneralSecurityException e) {
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throw new ApplicationException(e);
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}
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}
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@Override
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public byte[] getSignature(byte[] data, PrivateKey privateKey) {
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try {
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ECParameterSpec spec = new ECParameterSpec(
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EC_CURVE_PARAMETERS.getCurve(),
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EC_CURVE_PARAMETERS.getG(),
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EC_CURVE_PARAMETERS.getN(),
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EC_CURVE_PARAMETERS.getH(),
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EC_CURVE_PARAMETERS.getSeed()
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);
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BigInteger d = keyToBigInt(privateKey.getPrivateSigningKey());
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KeySpec keySpec = new ECPrivateKeySpec(d, spec);
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java.security.PrivateKey privKey = KeyFactory.getInstance(ALGORITHM_ECDSA, provider)
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.generatePrivate(keySpec);
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Signature sig = Signature.getInstance(ALGORITHM_ECDSA, provider);
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sig.initSign(privKey);
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sig.update(data);
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return sig.sign();
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} catch (GeneralSecurityException e) {
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throw new ApplicationException(e);
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}
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}
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@Override
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public byte[] multiply(byte[] K, byte[] r) {
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return keyToPoint(K).multiply(keyToBigInt(r)).normalize().getEncoded(false);
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}
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@Override
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public byte[] createPoint(byte[] x, byte[] y) {
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return EC_CURVE_PARAMETERS.getCurve().createPoint(
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new BigInteger(1, x),
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new BigInteger(1, y)
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).getEncoded(false);
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}
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}
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