Collapse some v2 interfaces now that there's no v1.
Moxie Marlinspike
11 years ago
parent
1d07ca3e6f
commit
cebad39422
@ -1,252 +0,0 @@
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package org.whispersystems.textsecure.crypto;
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import android.content.Context;
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import android.util.Log;
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import android.util.Pair;
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import org.whispersystems.textsecure.crypto.ecc.Curve;
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import org.whispersystems.textsecure.crypto.ecc.ECKeyPair;
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import org.whispersystems.textsecure.crypto.ecc.ECPublicKey;
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import org.whispersystems.textsecure.crypto.protocol.CiphertextMessage;
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import org.whispersystems.textsecure.crypto.protocol.PreKeyWhisperMessage;
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import org.whispersystems.textsecure.crypto.protocol.WhisperMessageV2;
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import org.whispersystems.textsecure.crypto.ratchet.ChainKey;
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import org.whispersystems.textsecure.crypto.ratchet.MessageKeys;
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import org.whispersystems.textsecure.crypto.ratchet.RootKey;
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import org.whispersystems.textsecure.storage.RecipientDevice;
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import org.whispersystems.textsecure.storage.SessionRecordV2;
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import org.whispersystems.textsecure.storage.SessionState;
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import org.whispersystems.textsecure.util.Conversions;
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import java.security.InvalidAlgorithmParameterException;
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import java.security.NoSuchAlgorithmException;
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import java.util.List;
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import javax.crypto.BadPaddingException;
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import javax.crypto.Cipher;
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import javax.crypto.IllegalBlockSizeException;
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import javax.crypto.NoSuchPaddingException;
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import javax.crypto.spec.IvParameterSpec;
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import javax.crypto.spec.SecretKeySpec;
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public class SessionCipherV2 extends SessionCipher {
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private final Context context;
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private final MasterSecret masterSecret;
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private final RecipientDevice recipient;
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public SessionCipherV2(Context context,
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MasterSecret masterSecret,
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RecipientDevice recipient)
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{
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this.context = context;
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this.masterSecret = masterSecret;
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this.recipient = recipient;
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}
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@Override
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public CiphertextMessage encrypt(byte[] paddedMessage) {
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synchronized (SESSION_LOCK) {
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SessionRecordV2 sessionRecord = getSessionRecord();
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SessionState sessionState = sessionRecord.getSessionState();
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ChainKey chainKey = sessionState.getSenderChainKey();
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MessageKeys messageKeys = chainKey.getMessageKeys();
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ECPublicKey senderEphemeral = sessionState.getSenderEphemeral();
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int previousCounter = sessionState.getPreviousCounter();
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byte[] ciphertextBody = getCiphertext(messageKeys, paddedMessage);
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CiphertextMessage ciphertextMessage = new WhisperMessageV2(messageKeys.getMacKey(),
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senderEphemeral, chainKey.getIndex(),
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previousCounter, ciphertextBody);
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if (sessionState.hasPendingPreKey()) {
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Pair<Integer, ECPublicKey> pendingPreKey = sessionState.getPendingPreKey();
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int localRegistrationId = sessionState.getLocalRegistrationId();
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ciphertextMessage = new PreKeyWhisperMessage(localRegistrationId, pendingPreKey.first,
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pendingPreKey.second,
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sessionState.getLocalIdentityKey(),
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(WhisperMessageV2) ciphertextMessage);
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}
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sessionState.setSenderChainKey(chainKey.getNextChainKey());
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sessionRecord.save();
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return ciphertextMessage;
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}
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}
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@Override
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public byte[] decrypt(byte[] decodedMessage)
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throws InvalidMessageException, DuplicateMessageException, LegacyMessageException
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{
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synchronized (SESSION_LOCK) {
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SessionRecordV2 sessionRecord = getSessionRecord();
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SessionState sessionState = sessionRecord.getSessionState();
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List<SessionState> previousStates = sessionRecord.getPreviousSessions();
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try {
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byte[] plaintext = decrypt(sessionState, decodedMessage);
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sessionRecord.save();
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return plaintext;
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} catch (InvalidMessageException e) {
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Log.w("SessionCipherV2", e);
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}
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for (SessionState previousState : previousStates) {
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try {
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Log.w("SessionCipherV2", "Attempting decrypt on previous state...");
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byte[] plaintext = decrypt(previousState, decodedMessage);
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sessionRecord.save();
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return plaintext;
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} catch (InvalidMessageException e) {
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Log.w("SessionCipherV2", e);
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}
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}
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throw new InvalidMessageException("No valid sessions.");
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}
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}
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public byte[] decrypt(SessionState sessionState, byte[] decodedMessage)
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throws InvalidMessageException, DuplicateMessageException, LegacyMessageException
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{
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if (!sessionState.hasSenderChain()) {
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throw new InvalidMessageException("Uninitialized session!");
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}
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WhisperMessageV2 ciphertextMessage = new WhisperMessageV2(decodedMessage);
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ECPublicKey theirEphemeral = ciphertextMessage.getSenderEphemeral();
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int counter = ciphertextMessage.getCounter();
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ChainKey chainKey = getOrCreateChainKey(sessionState, theirEphemeral);
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MessageKeys messageKeys = getOrCreateMessageKeys(sessionState, theirEphemeral,
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chainKey, counter);
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ciphertextMessage.verifyMac(messageKeys.getMacKey());
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byte[] plaintext = getPlaintext(messageKeys, ciphertextMessage.getBody());
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sessionState.clearPendingPreKey();
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return plaintext;
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}
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@Override
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public int getRemoteRegistrationId() {
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synchronized (SESSION_LOCK) {
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SessionRecordV2 sessionRecord = getSessionRecord();
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return sessionRecord.getSessionState().getRemoteRegistrationId();
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}
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}
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private ChainKey getOrCreateChainKey(SessionState sessionState, ECPublicKey theirEphemeral)
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throws InvalidMessageException
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{
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try {
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if (sessionState.hasReceiverChain(theirEphemeral)) {
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return sessionState.getReceiverChainKey(theirEphemeral);
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} else {
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RootKey rootKey = sessionState.getRootKey();
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ECKeyPair ourEphemeral = sessionState.getSenderEphemeralPair();
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Pair<RootKey, ChainKey> receiverChain = rootKey.createChain(theirEphemeral, ourEphemeral);
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ECKeyPair ourNewEphemeral = Curve.generateKeyPair(true);
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Pair<RootKey, ChainKey> senderChain = receiverChain.first.createChain(theirEphemeral, ourNewEphemeral);
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sessionState.setRootKey(senderChain.first);
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sessionState.addReceiverChain(theirEphemeral, receiverChain.second);
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sessionState.setPreviousCounter(sessionState.getSenderChainKey().getIndex()-1);
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sessionState.setSenderChain(ourNewEphemeral, senderChain.second);
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return receiverChain.second;
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}
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} catch (InvalidKeyException e) {
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throw new InvalidMessageException(e);
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}
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}
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private MessageKeys getOrCreateMessageKeys(SessionState sessionState,
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ECPublicKey theirEphemeral,
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ChainKey chainKey, int counter)
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throws InvalidMessageException, DuplicateMessageException
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{
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if (chainKey.getIndex() > counter) {
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if (sessionState.hasMessageKeys(theirEphemeral, counter)) {
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return sessionState.removeMessageKeys(theirEphemeral, counter);
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} else {
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throw new DuplicateMessageException("Received message with old counter: " +
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chainKey.getIndex() + " , " + counter);
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}
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}
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if (chainKey.getIndex() - counter > 2000) {
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throw new InvalidMessageException("Over 2000 messages into the future!");
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}
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while (chainKey.getIndex() < counter) {
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MessageKeys messageKeys = chainKey.getMessageKeys();
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sessionState.setMessageKeys(theirEphemeral, messageKeys);
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chainKey = chainKey.getNextChainKey();
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}
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sessionState.setReceiverChainKey(theirEphemeral, chainKey.getNextChainKey());
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return chainKey.getMessageKeys();
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}
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private byte[] getCiphertext(MessageKeys messageKeys, byte[] plaintext) {
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try {
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Cipher cipher = getCipher(Cipher.ENCRYPT_MODE,
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messageKeys.getCipherKey(),
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messageKeys.getCounter());
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return cipher.doFinal(plaintext);
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} catch (IllegalBlockSizeException e) {
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throw new AssertionError(e);
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} catch (BadPaddingException e) {
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throw new AssertionError(e);
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}
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}
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private byte[] getPlaintext(MessageKeys messageKeys, byte[] cipherText) {
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try {
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Cipher cipher = getCipher(Cipher.DECRYPT_MODE,
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messageKeys.getCipherKey(),
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messageKeys.getCounter());
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return cipher.doFinal(cipherText);
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} catch (IllegalBlockSizeException e) {
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throw new AssertionError(e);
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} catch (BadPaddingException e) {
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throw new AssertionError(e);
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}
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}
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private Cipher getCipher(int mode, SecretKeySpec key, int counter) {
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try {
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Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding");
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byte[] ivBytes = new byte[16];
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Conversions.intToByteArray(ivBytes, 0, counter);
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IvParameterSpec iv = new IvParameterSpec(ivBytes);
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cipher.init(mode, key, iv);
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return cipher;
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} catch (NoSuchAlgorithmException e) {
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throw new AssertionError(e);
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} catch (NoSuchPaddingException e) {
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throw new AssertionError(e);
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} catch (java.security.InvalidKeyException e) {
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throw new AssertionError(e);
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} catch (InvalidAlgorithmParameterException e) {
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throw new AssertionError(e);
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}
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}
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private SessionRecordV2 getSessionRecord() {
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return new SessionRecordV2(context, masterSecret, recipient);
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}
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}
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