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https://github.com/signalapp/Signal-Android.git
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b8f663b69c
1) Move all the crypto classes from securesms.crypto. 2) Move all the crypto storage from securesms.database.keys 3) Replace the old imported BC code with spongycastle.
86 lines
3.1 KiB
Java
86 lines
3.1 KiB
Java
/**
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* Copyright (C) 2011 Whisper Systems
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package org.whispersystems.textsecure.crypto;
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import java.security.InvalidKeyException;
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import java.security.NoSuchAlgorithmException;
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import java.util.Arrays;
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import javax.crypto.Mac;
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import javax.crypto.spec.SecretKeySpec;
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import org.whispersystems.textsecure.util.Hex;
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import android.util.Log;
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public class MessageMac {
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public static final int MAC_LENGTH = 10;
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private static byte[] calculateMac(byte[] message, int offset, int length, SecretKeySpec macKey) {
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try {
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Mac mac = Mac.getInstance("HmacSHA1");
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mac.init(macKey);
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assert(mac.getMacLength() >= MAC_LENGTH);
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mac.update(message, offset, length);
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byte[] macBytes = mac.doFinal();
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byte[] truncatedMacBytes = new byte[MAC_LENGTH];
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System.arraycopy(macBytes, 0, truncatedMacBytes, 0, truncatedMacBytes.length);
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return truncatedMacBytes;
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} catch (NoSuchAlgorithmException e) {
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throw new IllegalArgumentException(e);
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} catch (InvalidKeyException e) {
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throw new IllegalArgumentException(e);
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}
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}
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public static byte[] buildMessageWithMac(byte[] message, SecretKeySpec macKey) {
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byte[] macBytes = calculateMac(message, 0, message.length, macKey);
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byte[] combined = new byte[macBytes.length + message.length];
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System.arraycopy(message, 0, combined, 0, message.length);
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System.arraycopy(macBytes, 0, combined, message.length, macBytes.length);
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return combined;
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}
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public static byte[] getMessageWithoutMac(byte[] message) throws InvalidMacException {
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if (message == null || message.length <= MAC_LENGTH)
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throw new InvalidMacException("Message shorter than MAC!");
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byte[] strippedMessage = new byte[message.length - MAC_LENGTH];
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System.arraycopy(message, 0, strippedMessage, 0, strippedMessage.length);
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return strippedMessage;
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}
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public static void verifyMac(byte[] message, SecretKeySpec macKey) throws InvalidMacException {
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byte[] localMacBytes = calculateMac(message, 0, message.length - MAC_LENGTH, macKey);
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byte[] receivedMacBytes = new byte[MAC_LENGTH];
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System.arraycopy(message, message.length-MAC_LENGTH, receivedMacBytes, 0, receivedMacBytes.length);
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Log.w("mm", "Local Mac: " + Hex.toString(localMacBytes));
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Log.w("mm", "Remot Mac: " + Hex.toString(receivedMacBytes));
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if (!Arrays.equals(localMacBytes, receivedMacBytes))
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throw new InvalidMacException("MAC on message does not match calculated MAC.");
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}
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}
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