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Remove verification tag.
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1) Remove verification tag from PreKeyWhisperMessage.

2) Include sender and recipient identity keys in the MAC of
   each WhisperMessage.
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@moxie0
moxie0 committed Oct 20, 2014
1 parent 641ac9a commit 5ea3b30
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Showing 13 changed files with 80 additions and 556 deletions.
1 change: 0 additions & 1 deletion libaxolotl/protobuf/LocalStorageProtocol.proto
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,6 @@ message SessionStructure {

optional bool needsRefresh = 12;
optional bytes aliceBaseKey = 13;
optional bytes verification = 14;
}

message RecordStructure {
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1 change: 0 additions & 1 deletion libaxolotl/protobuf/WhisperTextProtocol.proto
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Expand Up @@ -16,7 +16,6 @@ message PreKeyWhisperMessage {
optional uint32 signedPreKeyId = 6;
optional bytes baseKey = 2;
optional bytes identityKey = 3;
optional bytes verification = 7;
optional bytes message = 4; // WhisperMessage
}

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76 changes: 0 additions & 76 deletions libaxolotl/src/androidTest/java/org/whispersystems/test/SessionBuilderTest.java
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Expand Up @@ -406,82 +406,6 @@ public void testRepeatBundleMessageV3() throws InvalidKeyException, UntrustedIde

}

public void testBadVerificationTagV3() throws InvalidKeyException, UntrustedIdentityException, InvalidVersionException, InvalidMessageException, InvalidKeyIdException, DuplicateMessageException, LegacyMessageException, NoSessionException {
SessionStore aliceSessionStore = new InMemorySessionStore();
SignedPreKeyStore aliceSignedPreKeyStore = new InMemorySignedPreKeyStore();
PreKeyStore alicePreKeyStore = new InMemoryPreKeyStore();
IdentityKeyStore aliceIdentityKeyStore = new InMemoryIdentityKeyStore();
SessionBuilder aliceSessionBuilder = new SessionBuilder(aliceSessionStore, alicePreKeyStore,
aliceSignedPreKeyStore,
aliceIdentityKeyStore,
BOB_RECIPIENT_ID, 1);

SessionStore bobSessionStore = new InMemorySessionStore();
PreKeyStore bobPreKeyStore = new InMemoryPreKeyStore();
SignedPreKeyStore bobSignedPreKeyStore = new InMemorySignedPreKeyStore();
IdentityKeyStore bobIdentityKeyStore = new InMemoryIdentityKeyStore();


ECKeyPair bobPreKeyPair = Curve.generateKeyPair(true);
ECKeyPair bobSignedPreKeyPair = Curve.generateKeyPair(true);
byte[] bobSignedPreKeySignature = Curve.calculateSignature(bobIdentityKeyStore.getIdentityKeyPair().getPrivateKey(),
bobSignedPreKeyPair.getPublicKey().serialize());

PreKeyBundle bobPreKey = new PreKeyBundle(bobIdentityKeyStore.getLocalRegistrationId(), 1,
31337, bobPreKeyPair.getPublicKey(),
22, bobSignedPreKeyPair.getPublicKey(), bobSignedPreKeySignature,
bobIdentityKeyStore.getIdentityKeyPair().getPublicKey());

bobPreKeyStore.storePreKey(31337, new PreKeyRecord(bobPreKey.getPreKeyId(), bobPreKeyPair));
bobSignedPreKeyStore.storeSignedPreKey(22, new SignedPreKeyRecord(22, System.currentTimeMillis(), bobSignedPreKeyPair, bobSignedPreKeySignature));

aliceSessionBuilder.process(bobPreKey);

String originalMessage = "L'homme est condamné à être libre";
SessionCipher aliceSessionCipher = new SessionCipher(aliceSessionStore, alicePreKeyStore, aliceSignedPreKeyStore, aliceIdentityKeyStore, BOB_RECIPIENT_ID, 1);
CiphertextMessage outgoingMessageOne = aliceSessionCipher.encrypt(originalMessage.getBytes());

assertTrue(outgoingMessageOne.getType() == CiphertextMessage.PREKEY_TYPE);

PreKeyWhisperMessage incomingMessage = new PreKeyWhisperMessage(outgoingMessageOne.serialize());

SessionCipher bobSessionCipher = new SessionCipher(bobSessionStore, bobPreKeyStore, bobSignedPreKeyStore, bobIdentityKeyStore, ALICE_RECIPIENT_ID, 1);

for (int i=0;i<incomingMessage.getVerification().length * 8;i++) {
byte[] modifiedVerification = new byte[incomingMessage.getVerification().length];
System.arraycopy(incomingMessage.getVerification(), 0, modifiedVerification, 0, modifiedVerification.length);
modifiedVerification[i / 8] ^= (0x01 << i % 8);

PreKeyWhisperMessage modifiedMessage = new PreKeyWhisperMessage(incomingMessage.getMessageVersion(),
incomingMessage.getRegistrationId(),
incomingMessage.getPreKeyId(),
incomingMessage.getSignedPreKeyId(),
incomingMessage.getBaseKey(),
incomingMessage.getIdentityKey(),
modifiedVerification,
incomingMessage.getWhisperMessage());

try {
bobSessionCipher.decrypt(modifiedMessage);
throw new AssertionError("Modified verification tag passed!");
} catch (InvalidKeyException e) {
// good
}
}

PreKeyWhisperMessage unmodifiedMessage = new PreKeyWhisperMessage(incomingMessage.getMessageVersion(),
incomingMessage.getRegistrationId(),
incomingMessage.getPreKeyId(),
incomingMessage.getSignedPreKeyId(),
incomingMessage.getBaseKey(),
incomingMessage.getIdentityKey(),
incomingMessage.getVerification(),
incomingMessage.getWhisperMessage());

bobSessionCipher.decrypt(unmodifiedMessage);
}


public void testBasicKeyExchange() throws InvalidKeyException, LegacyMessageException, InvalidMessageException, DuplicateMessageException, UntrustedIdentityException, StaleKeyExchangeException, InvalidVersionException, NoSessionException {
SessionStore aliceSessionStore = new InMemorySessionStore();
PreKeyStore alicePreKeyStore = new InMemoryPreKeyStore();
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90 changes: 0 additions & 90 deletions libaxolotl/src/androidTest/java/org/whispersystems/test/ratchet/VerifyKeyTest.java
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This file was deleted.

6 changes: 0 additions & 6 deletions libaxolotl/src/main/java/org/whispersystems/libaxolotl/SessionBuilder.java
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Original file line number Diff line number Diff line change
Expand Up @@ -23,8 +23,6 @@
import org.whispersystems.libaxolotl.util.Medium;
import org.whispersystems.libaxolotl.util.guava.Optional;

import java.security.MessageDigest;

/**
* SessionBuilder is responsible for setting up encrypted sessions.
* Once a session has been established, {@link org.whispersystems.libaxolotl.SessionCipher}
Expand Down Expand Up @@ -143,10 +141,6 @@ private boolean processV3(PreKeyWhisperMessage message)

RatchetingSession.initializeSession(sessionRecord.getSessionState(), message.getMessageVersion(), parameters.create());

if (!MessageDigest.isEqual(sessionRecord.getSessionState().getVerification(), message.getVerification())) {
throw new InvalidKeyException("Verification secret mismatch!");
}

sessionRecord.getSessionState().setLocalRegistrationId(identityKeyStore.getLocalRegistrationId());
sessionRecord.getSessionState().setRemoteRegistrationId(message.getRegistrationId());
sessionRecord.getSessionState().setAliceBaseKey(message.getBaseKey().serialize());
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10 changes: 7 additions & 3 deletions libaxolotl/src/main/java/org/whispersystems/libaxolotl/SessionCipher.java
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Original file line number Diff line number Diff line change
Expand Up @@ -105,7 +105,9 @@ public CiphertextMessage encrypt(byte[] paddedMessage) {
byte[] ciphertextBody = getCiphertext(messageKeys, paddedMessage);
CiphertextMessage ciphertextMessage = new WhisperMessage(sessionVersion, messageKeys.getMacKey(),
senderEphemeral, chainKey.getIndex(),
previousCounter, ciphertextBody);
previousCounter, ciphertextBody,
sessionState.getLocalIdentityKey(),
sessionState.getRemoteIdentityKey());

if (sessionState.hasUnacknowledgedPreKeyMessage()) {
UnacknowledgedPreKeyMessageItems items = sessionState.getUnacknowledgedPreKeyMessageItems();
Expand All @@ -114,7 +116,6 @@ public CiphertextMessage encrypt(byte[] paddedMessage) {
ciphertextMessage = new PreKeyWhisperMessage(sessionVersion, localRegistrationId, items.getPreKeyId(),
items.getSignedPreKeyId(), items.getBaseKey(),
sessionState.getLocalIdentityKey(),
sessionState.getVerification(),
(WhisperMessage) ciphertextMessage);
}

Expand Down Expand Up @@ -229,7 +230,10 @@ private byte[] decrypt(SessionState sessionState, WhisperMessage ciphertextMessa
MessageKeys messageKeys = getOrCreateMessageKeys(sessionState, theirEphemeral,
chainKey, counter);

ciphertextMessage.verifyMac(messageKeys.getMacKey());
ciphertextMessage.verifyMac(ciphertextMessage.getMessageVersion(),
sessionState.getRemoteIdentityKey(),
sessionState.getLocalIdentityKey(),
messageKeys.getMacKey());

byte[] plaintext = getPlaintext(messageKeys, ciphertextMessage.getBody());

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12 changes: 1 addition & 11 deletions libaxolotl/src/main/java/org/whispersystems/libaxolotl/protocol/PreKeyWhisperMessage.java
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Expand Up @@ -37,7 +37,6 @@ public class PreKeyWhisperMessage implements CiphertextMessage {
private final int signedPreKeyId;
private final ECPublicKey baseKey;
private final IdentityKey identityKey;
private final byte[] verification;
private final WhisperMessage message;
private final byte[] serialized;

Expand All @@ -57,7 +56,6 @@ public PreKeyWhisperMessage(byte[] serialized)

if ((version == 2 && !preKeyWhisperMessage.hasPreKeyId()) ||
(version == 3 && !preKeyWhisperMessage.hasSignedPreKeyId()) ||
(version == 3 && !preKeyWhisperMessage.hasVerification()) ||
!preKeyWhisperMessage.hasBaseKey() ||
!preKeyWhisperMessage.hasIdentityKey() ||
!preKeyWhisperMessage.hasMessage())
Expand All @@ -71,24 +69,21 @@ public PreKeyWhisperMessage(byte[] serialized)
this.signedPreKeyId = preKeyWhisperMessage.hasSignedPreKeyId() ? preKeyWhisperMessage.getSignedPreKeyId() : -1;
this.baseKey = Curve.decodePoint(preKeyWhisperMessage.getBaseKey().toByteArray(), 0);
this.identityKey = new IdentityKey(Curve.decodePoint(preKeyWhisperMessage.getIdentityKey().toByteArray(), 0));
this.verification = preKeyWhisperMessage.getVerification().toByteArray();
this.message = new WhisperMessage(preKeyWhisperMessage.getMessage().toByteArray());
} catch (InvalidProtocolBufferException | InvalidKeyException | LegacyMessageException e) {
throw new InvalidMessageException(e);
}
}

public PreKeyWhisperMessage(int messageVersion, int registrationId, int preKeyId, int signedPreKeyId,
ECPublicKey baseKey, IdentityKey identityKey, byte[] verification,
WhisperMessage message)
ECPublicKey baseKey, IdentityKey identityKey, WhisperMessage message)
{
this.version = messageVersion;
this.registrationId = registrationId;
this.preKeyId = preKeyId;
this.signedPreKeyId = signedPreKeyId;
this.baseKey = baseKey;
this.identityKey = identityKey;
this.verification = verification;
this.message = message;

byte[] versionBytes = {ByteUtil.intsToByteHighAndLow(this.version, CURRENT_VERSION)};
Expand All @@ -97,7 +92,6 @@ public PreKeyWhisperMessage(int messageVersion, int registrationId, int preKeyId
.setSignedPreKeyId(signedPreKeyId)
.setBaseKey(ByteString.copyFrom(baseKey.serialize()))
.setIdentityKey(ByteString.copyFrom(identityKey.serialize()))
.setVerification(ByteString.copyFrom(verification))
.setMessage(ByteString.copyFrom(message.serialize()))
.setRegistrationId(registrationId)
.build().toByteArray();
Expand Down Expand Up @@ -129,10 +123,6 @@ public ECPublicKey getBaseKey() {
return baseKey;
}

public byte[] getVerification() {
return verification;
}

public WhisperMessage getWhisperMessage() {
return message;
}
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