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Using JCE implementation as a default instead of BouncyCastle's AESFastEngine
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-175
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4 files changed

+281
-175
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‎src/main/java/org/cryptomator/siv/JceAesBlockCipher.java

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package org.cryptomator.siv;
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/*******************************************************************************
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* Copyright (c) 2016 Sebastian Stenzel
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* This file is licensed under the terms of the MIT license.
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* See the LICENSE.txt file for more info.
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*
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* Contributors:
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* Sebastian Stenzel - initial API and implementation
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******************************************************************************/
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import java.nio.ByteBuffer;
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import java.security.InvalidKeyException;
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import java.security.Key;
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import java.security.NoSuchAlgorithmException;
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import javax.crypto.Cipher;
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import javax.crypto.NoSuchPaddingException;
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import javax.crypto.ShortBufferException;
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import javax.crypto.spec.SecretKeySpec;
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import org.bouncycastle.crypto.BlockCipher;
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import org.bouncycastle.crypto.CipherParameters;
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import org.bouncycastle.crypto.DataLengthException;
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import org.bouncycastle.crypto.params.KeyParameter;
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/**
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* Adapter class between BouncyCastle's {@link BlockCipher} and JCE's {@link Cipher} API.
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*/
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class JceAesBlockCipher implements BlockCipher {
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private static final String ALG_NAME = "AES";
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private static final String KEY_DESIGNATION = "AES";
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private static final String JCE_CIPHER_NAME = "AES/ECB/NoPadding";
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private final Cipher cipher;
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private Key key;
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private int opmode;
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public JceAesBlockCipher() {
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try {
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this.cipher = Cipher.getInstance(JCE_CIPHER_NAME); // defaults to SunJCE but allows to configure different providers
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} catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
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throw new IllegalStateException("Every implementation of the Java platform is required to support AES/ECB/NoPadding.");
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}
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}
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@Override
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public void init(boolean forEncryption, CipherParameters params) throws IllegalArgumentException {
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if (params instanceof KeyParameter) {
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init(forEncryption, (KeyParameter) params);
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} else {
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throw new IllegalArgumentException("Invalid or missing parameter of type KeyParameter.");
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}
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}
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private void init(boolean forEncryption, KeyParameter keyParam) throws IllegalArgumentException {
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this.key = new SecretKeySpec(keyParam.getKey(), KEY_DESIGNATION);
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this.opmode = forEncryption ? Cipher.ENCRYPT_MODE : Cipher.DECRYPT_MODE;
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try {
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cipher.init(opmode, key);
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} catch (InvalidKeyException e) {
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throw new IllegalArgumentException("Invalid key.", e);
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}
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}
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@Override
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public String getAlgorithmName() {
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return ALG_NAME;
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}
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@Override
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public int getBlockSize() {
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return cipher.getBlockSize();
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}
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@Override
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public int processBlock(byte[] in, int inOff, byte[] out, int outOff) throws DataLengthException, IllegalStateException {
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if (in.length - inOff < getBlockSize()) {
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throw new DataLengthException("Insufficient data in 'in'.");
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}
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ByteBuffer inBuf = ByteBuffer.wrap(in, inOff, getBlockSize());
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ByteBuffer outBuf = ByteBuffer.wrap(out, outOff, out.length - outOff);
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try {
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return cipher.update(inBuf, outBuf);
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} catch (ShortBufferException e) {
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throw new DataLengthException("Insufficient space in 'out'.");
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}
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}
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@Override
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public void reset() {
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if (key == null) {
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return; // no-op if init has not been called yet.
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}
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try {
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cipher.init(opmode, key);
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} catch (InvalidKeyException e) {
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throw new IllegalStateException("cipher.init(...) already invoked successfully earlier with same parameters.");
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}
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}
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}

‎src/main/java/org/cryptomator/siv/SivMode.java

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@@ -18,7 +18,6 @@
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import org.bouncycastle.crypto.BlockCipher;
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import org.bouncycastle.crypto.CipherParameters;
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import org.bouncycastle.crypto.Mac;
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import org.bouncycastle.crypto.engines.AESFastEngine;
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import org.bouncycastle.crypto.engines.AESLightEngine;
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import org.bouncycastle.crypto.macs.CMac;
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import org.bouncycastle.crypto.paddings.ISO7816d4Padding;
@@ -35,7 +34,7 @@ public final class SivMode {
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private final BlockCipherFactory cipherFactory;
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/**
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* Creates an AES-SIV instance using BouncyCastle's {@link AESFastEngine}, which should normally be the best choice.<br>
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* Creates an AES-SIV instance using JCE's cipher implementation, which should normally be the best choice.<br>
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*
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* For embedded systems, you might want to consider using {@link #SivMode(BlockCipherFactory)} with {@link AESLightEngine} instead.
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*
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@Override
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public BlockCipher create() {
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return new AESFastEngine();
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return new JceAesBlockCipher();
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}
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});

‎src/test/java/org/cryptomator/siv/JceAesBlockCipherTest.java

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package org.cryptomator.siv;
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/*******************************************************************************
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* Copyright (c) 2016 Sebastian Stenzel
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* This file is licensed under the terms of the MIT license.
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* See the LICENSE.txt file for more info.
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*
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* Contributors:
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* Sebastian Stenzel - initial API and implementation
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******************************************************************************/
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import org.bouncycastle.crypto.DataLengthException;
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import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
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import org.bouncycastle.crypto.params.KeyParameter;
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import org.junit.Assert;
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import org.junit.Rule;
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import org.junit.Test;
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import org.junit.rules.ExpectedException;
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public class JceAesBlockCipherTest {
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@Rule
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public final ExpectedException thrown = ExpectedException.none();
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@Test
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public void testInitWithNullParam() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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thrown.expect(IllegalArgumentException.class);
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thrown.expectMessage("missing parameter of type KeyParameter");
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cipher.init(true, null);
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}
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@Test
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public void testInitWithMissingKey() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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thrown.expect(IllegalArgumentException.class);
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thrown.expectMessage("missing parameter of type KeyParameter");
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cipher.init(true, new AsymmetricKeyParameter(true));
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}
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@Test
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public void testInitWithInvalidKey() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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thrown.expect(IllegalArgumentException.class);
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thrown.expectMessage("Invalid key");
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cipher.init(true, new KeyParameter(new byte[7]));
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}
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@Test
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public void testInitForEncryption() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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cipher.init(true, new KeyParameter(new byte[16]));
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}
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@Test
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public void testInitForDecryption() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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cipher.init(false, new KeyParameter(new byte[16]));
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}
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@Test
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public void testGetAlgorithmName() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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Assert.assertEquals("AES", cipher.getAlgorithmName());
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}
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@Test
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public void testGetBlockSize() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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Assert.assertEquals(16, cipher.getBlockSize());
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}
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@Test
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public void testProcessBlockWithUninitializedCipher() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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thrown.expect(IllegalStateException.class);
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cipher.processBlock(new byte[16], 0, new byte[16], 0);
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}
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@Test
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public void testProcessBlockWithUnsufficientInput() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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cipher.init(true, new KeyParameter(new byte[16]));
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thrown.expect(DataLengthException.class);
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thrown.expectMessage("Insufficient data in 'in'");
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cipher.processBlock(new byte[16], 1, new byte[16], 0);
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}
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@Test
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public void testProcessBlockWithUnsufficientOutput() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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cipher.init(true, new KeyParameter(new byte[16]));
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thrown.expect(DataLengthException.class);
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thrown.expectMessage("Insufficient space in 'out'");
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cipher.processBlock(new byte[16], 0, new byte[16], 1);
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}
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@Test
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public void testProcessBlock() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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cipher.init(true, new KeyParameter(new byte[16]));
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byte[] ciphertext = new byte[16];
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int encrypted = cipher.processBlock(new byte[20], 0, ciphertext, 0);
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Assert.assertEquals(16, encrypted);
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cipher.init(false, new KeyParameter(new byte[16]));
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byte[] cleartext = new byte[16];
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int decrypted = cipher.processBlock(ciphertext, 0, cleartext, 0);
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Assert.assertEquals(16, decrypted);
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Assert.assertArrayEquals(new byte[16], cleartext);
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}
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@Test
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public void testResetBeforeInitDoesNotThrowExceptions() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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cipher.reset();
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}
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@Test
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public void testResetAfterInitDoesNotThrowExceptions() {
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JceAesBlockCipher cipher = new JceAesBlockCipher();
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cipher.init(true, new KeyParameter(new byte[16]));
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cipher.reset();
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}
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}

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