153 lines
5.2 KiB
Java
153 lines
5.2 KiB
Java
/*
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* The MIT License
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*
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* Copyright 2016 Ahseya.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package libKonogonka.xtsaes;
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import net.jcip.annotations.NotThreadSafe;
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import org.bouncycastle.crypto.BlockCipher;
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import org.bouncycastle.crypto.DataLengthException;
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import org.bouncycastle.crypto.engines.AESEngine;
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import org.bouncycastle.crypto.params.KeyParameter;
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import java.util.Arrays;
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import java.util.Objects;
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/**
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* XTS core functions.
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*
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* @author Ahseya
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*
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* Class updated for NCAs usage.
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* */
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@NotThreadSafe
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class XTSCore {
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private static final int BLOCK_SIZE = 16;
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private final BlockCipher cipher;
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private final XTSTweak tweak;
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private boolean forEncryption;
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XTSCore(BlockCipher cipher, XTSTweak tweak) {
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this.cipher = Objects.requireNonNull(cipher, "cipher");
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this.tweak = Objects.requireNonNull(tweak, "tweak");
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}
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XTSCore(XTSTweak tweak) {
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this(new AESEngine(), tweak);
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}
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XTSCore(boolean isDefault) {
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this(new XTSTweak(isDefault));
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}
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XTSCore init(boolean forEncryption, KeyParameter key) throws IllegalArgumentException {
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byte[] k = key.getKey();
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if (k.length != 32 && k.length != 64) {
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throw new IllegalArgumentException("bad key length: " + k.length);
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}
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byte[] key1 = Arrays.copyOfRange(k, 0, k.length / 2);
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byte[] key2 = Arrays.copyOfRange(k, k.length / 2, k.length);
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return init(forEncryption, new KeyParameter(key1), new KeyParameter(key2));
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}
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XTSCore init(boolean forEncryption, KeyParameter key1, KeyParameter key2) throws IllegalArgumentException {
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cipher.init(forEncryption, key1);
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tweak.init(key2);
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this.forEncryption = forEncryption;
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return this;
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}
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XTSCore reset(long tweakValue) throws DataLengthException, IllegalStateException {
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tweak.reset(tweakValue);
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return this;
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}
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String getAlgorithmName() {
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return cipher.getAlgorithmName();
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}
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int getBlockSize() {
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return BLOCK_SIZE;
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}
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int processBlock(byte[] in, int inOff, byte[] out, int outOff) throws DataLengthException, IllegalStateException {
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byte[] tweakValue = tweak.value();
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doProcessBlock(in, inOff, out, outOff, tweakValue);
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tweak.next();
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return BLOCK_SIZE;
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}
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int doProcessBlock(byte[] in, int inOff, byte[] out, int outOff, byte[] tweakValue)
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throws DataLengthException, IllegalStateException {
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merge(in, inOff, out, outOff, tweakValue);
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cipher.processBlock(out, outOff, out, outOff);
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merge(out, outOff, out, outOff, tweakValue);
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return BLOCK_SIZE;
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}
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void merge(byte[] in, int inOff, byte[] out, int outOff, byte[] tweak) {
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for (int i = 0; i < BLOCK_SIZE; i++) {
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out[i + outOff] = (byte) (in[i + inOff] ^ tweak[i]);
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}
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}
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int processPartial(byte[] in, int inOff, byte[] out, int outOff, int length) {
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if (length <= BLOCK_SIZE) {
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throw new DataLengthException("input buffer too small/ missing last two blocks: " + length);
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}
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if (length >= BLOCK_SIZE * 2) {
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throw new DataLengthException("input buffer too large/ non-partial final block: " + length);
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}
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byte[] tweakA = tweak.value();
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byte[] tweakB = tweak.next().value();
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return forEncryption
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? XTSCore.this.doProcessPartial(in, inOff, out, outOff, length, tweakA, tweakB)
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: XTSCore.this.doProcessPartial(in, inOff, out, outOff, length, tweakB, tweakA);
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}
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int doProcessPartial(byte[] in, int inOff, byte[] out, int outOff, int length, byte[] tweakA, byte[] tweakB)
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throws DataLengthException, IllegalStateException {
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// M-1 block
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doProcessBlock(in, inOff, out, outOff, tweakA);
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// Cipher stealing
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byte[] buffer = Arrays.copyOfRange(out, outOff, outOff + BLOCK_SIZE);
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System.arraycopy(in, inOff + BLOCK_SIZE, buffer, 0, length - BLOCK_SIZE);
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// M block
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doProcessBlock(buffer, 0, buffer, 0, tweakB);
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// Copy over final block pair
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System.arraycopy(out, outOff, out, outOff + BLOCK_SIZE, length - BLOCK_SIZE);
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System.arraycopy(buffer, 0, out, outOff, BLOCK_SIZE);
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return length;
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}
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}
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