Collapse RatchetingSessionV2 and RatchetingSessionV3.

This commit is contained in:
Moxie Marlinspike 2014-07-05 13:42:07 -07:00
parent 811479d168
commit d6c5e92c9d
5 changed files with 72 additions and 202 deletions

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@ -12,8 +12,7 @@ import org.whispersystems.libaxolotl.SessionCipher;
import org.whispersystems.libaxolotl.ecc.Curve;
import org.whispersystems.libaxolotl.ecc.ECKeyPair;
import org.whispersystems.libaxolotl.protocol.CiphertextMessage;
import org.whispersystems.libaxolotl.ratchet.RatchetingSessionV2;
import org.whispersystems.libaxolotl.ratchet.RatchetingSessionV3;
import org.whispersystems.libaxolotl.ratchet.RatchetingSession;
import org.whispersystems.libaxolotl.state.SessionRecord;
import org.whispersystems.libaxolotl.state.SessionState;
import org.whispersystems.libaxolotl.state.SessionStore;
@ -136,13 +135,15 @@ public class SessionCipherTest extends AndroidTestCase {
ECKeyPair bobEphemeralKey = bobBaseKey;
RatchetingSessionV2.initializeSession(aliceSessionState, aliceBaseKey, bobBaseKey.getPublicKey(),
aliceEphemeralKey, bobEphemeralKey.getPublicKey(),
aliceIdentityKey, bobIdentityKey.getPublicKey());
RatchetingSession.initializeSession(aliceSessionState, 2, aliceBaseKey, bobBaseKey.getPublicKey(),
aliceEphemeralKey, bobEphemeralKey.getPublicKey(),
null, null,
aliceIdentityKey, bobIdentityKey.getPublicKey());
RatchetingSessionV2.initializeSession(bobSessionState, bobBaseKey, aliceBaseKey.getPublicKey(),
bobEphemeralKey, aliceEphemeralKey.getPublicKey(),
bobIdentityKey, aliceIdentityKey.getPublicKey());
RatchetingSession.initializeSession(bobSessionState, 2, bobBaseKey, aliceBaseKey.getPublicKey(),
bobEphemeralKey, aliceEphemeralKey.getPublicKey(),
null, null,
bobIdentityKey, aliceIdentityKey.getPublicKey());
}
private void initializeSessionsV3(SessionState aliceSessionState, SessionState bobSessionState)
@ -165,15 +166,15 @@ public class SessionCipherTest extends AndroidTestCase {
ECKeyPair bobPreKey = Curve.generateKeyPair(true);
RatchetingSessionV3.initializeSession(aliceSessionState, aliceBaseKey, bobBaseKey.getPublicKey(),
aliceEphemeralKey, bobEphemeralKey.getPublicKey(),
alicePreKey, bobPreKey.getPublicKey(),
aliceIdentityKey, bobIdentityKey.getPublicKey());
RatchetingSession.initializeSession(aliceSessionState, 3, aliceBaseKey, bobBaseKey.getPublicKey(),
aliceEphemeralKey, bobEphemeralKey.getPublicKey(),
alicePreKey, bobPreKey.getPublicKey(),
aliceIdentityKey, bobIdentityKey.getPublicKey());
RatchetingSessionV3.initializeSession(bobSessionState, bobBaseKey, aliceBaseKey.getPublicKey(),
bobEphemeralKey, aliceEphemeralKey.getPublicKey(),
bobPreKey, alicePreKey.getPublicKey(),
bobIdentityKey, aliceIdentityKey.getPublicKey());
RatchetingSession.initializeSession(bobSessionState, 3, bobBaseKey, aliceBaseKey.getPublicKey(),
bobEphemeralKey, aliceEphemeralKey.getPublicKey(),
bobPreKey, alicePreKey.getPublicKey(),
bobIdentityKey, aliceIdentityKey.getPublicKey());
}
}

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@ -5,16 +5,16 @@ import android.test.AndroidTestCase;
import org.whispersystems.libaxolotl.IdentityKey;
import org.whispersystems.libaxolotl.IdentityKeyPair;
import org.whispersystems.libaxolotl.InvalidKeyException;
import org.whispersystems.libaxolotl.state.SessionState;
import org.whispersystems.libaxolotl.ecc.Curve;
import org.whispersystems.libaxolotl.ecc.ECKeyPair;
import org.whispersystems.libaxolotl.ecc.ECPrivateKey;
import org.whispersystems.libaxolotl.ecc.ECPublicKey;
import org.whispersystems.libaxolotl.ratchet.RatchetingSessionV2;
import org.whispersystems.libaxolotl.ratchet.RatchetingSession;
import org.whispersystems.libaxolotl.state.SessionState;
import java.util.Arrays;
public class RatchetingSessionV2Test extends AndroidTestCase {
public class RatchetingSessionTest extends AndroidTestCase {
public void testRatchetingSessionAsBob() throws InvalidKeyException {
byte[] bobPublic = {(byte) 0x05, (byte) 0x2c, (byte) 0xb4, (byte) 0x97,
@ -107,9 +107,10 @@ public class RatchetingSessionV2Test extends AndroidTestCase {
SessionState session = new SessionState();
RatchetingSessionV2.initializeSession(session, bobBaseKey, aliceBasePublicKey,
bobEphemeralKey, aliceEphemeralPublicKey,
bobIdentityKey, aliceIdentityPublicKey);
RatchetingSession.initializeSession(session, 2, bobBaseKey, aliceBasePublicKey,
bobEphemeralKey, aliceEphemeralPublicKey,
null, null,
bobIdentityKey, aliceIdentityPublicKey);
assertTrue(session.getLocalIdentityKey().equals(bobIdentityKey.getPublicKey()));
assertTrue(session.getRemoteIdentityKey().equals(aliceIdentityPublicKey));
@ -204,9 +205,10 @@ public class RatchetingSessionV2Test extends AndroidTestCase {
SessionState session = new SessionState();
RatchetingSessionV2.initializeSession(session, aliceBaseKey, bobBasePublicKey,
aliceEphemeralKey, bobEphemeralPublicKey,
aliceIdentityKey, bobIdentityKey);
RatchetingSession.initializeSession(session, 2, aliceBaseKey, bobBasePublicKey,
aliceEphemeralKey, bobEphemeralPublicKey,
null, null,
aliceIdentityKey, bobIdentityKey);
assertTrue(session.getLocalIdentityKey().equals(aliceIdentityKey.getPublicKey()));
assertTrue(session.getRemoteIdentityKey().equals(bobIdentityKey));

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@ -7,8 +7,7 @@ import org.whispersystems.libaxolotl.ecc.ECKeyPair;
import org.whispersystems.libaxolotl.ecc.ECPublicKey;
import org.whispersystems.libaxolotl.protocol.KeyExchangeMessage;
import org.whispersystems.libaxolotl.protocol.PreKeyWhisperMessage;
import org.whispersystems.libaxolotl.ratchet.RatchetingSessionV2;
import org.whispersystems.libaxolotl.ratchet.RatchetingSessionV3;
import org.whispersystems.libaxolotl.ratchet.RatchetingSession;
import org.whispersystems.libaxolotl.state.DeviceKeyRecord;
import org.whispersystems.libaxolotl.state.DeviceKeyStore;
import org.whispersystems.libaxolotl.state.IdentityKeyStore;
@ -21,8 +20,6 @@ import org.whispersystems.libaxolotl.state.SessionStore;
import org.whispersystems.libaxolotl.util.KeyHelper;
import org.whispersystems.libaxolotl.util.Medium;
import java.util.Arrays;
/**
* SessionBuilder is responsible for setting up encrypted sessions.
* Once a session has been established, {@link org.whispersystems.libaxolotl.SessionCipher}
@ -138,11 +135,12 @@ public class SessionBuilder {
if (!simultaneousInitiate) sessionRecord.reset();
else sessionRecord.archiveCurrentState();
RatchetingSessionV3.initializeSession(sessionRecord.getSessionState(),
ourBaseKey, theirBaseKey,
ourEphemeralKey, theirEphemeralKey,
ourPreKey, theirPreKey,
ourIdentityKey, theirIdentityKey);
RatchetingSession.initializeSession(sessionRecord.getSessionState(),
message.getMessageVersion(),
ourBaseKey, theirBaseKey,
ourEphemeralKey, theirEphemeralKey,
ourPreKey, theirPreKey,
ourIdentityKey, theirIdentityKey);
sessionRecord.getSessionState().setLocalRegistrationId(identityKeyStore.getLocalRegistrationId());
sessionRecord.getSessionState().setRemoteRegistrationId(message.getRegistrationId());
@ -186,10 +184,12 @@ public class SessionBuilder {
if (!simultaneousInitiate) sessionRecord.reset();
else sessionRecord.archiveCurrentState();
RatchetingSessionV2.initializeSession(sessionRecord.getSessionState(),
ourBaseKey, theirBaseKey,
ourEphemeralKey, theirEphemeralKey,
ourIdentityKey, theirIdentityKey);
RatchetingSession.initializeSession(sessionRecord.getSessionState(),
message.getMessageVersion(),
ourBaseKey, theirBaseKey,
ourEphemeralKey, theirEphemeralKey,
null, null,
ourIdentityKey, theirIdentityKey);
sessionRecord.getSessionState().setLocalRegistrationId(identityKeyStore.getLocalRegistrationId());
sessionRecord.getSessionState().setRemoteRegistrationId(message.getRegistrationId());
@ -242,15 +242,11 @@ public class SessionBuilder {
if (sessionRecord.getSessionState().getNeedsRefresh()) sessionRecord.archiveCurrentState();
else sessionRecord.reset();
if (preKey.getDeviceKey() == null) {
RatchetingSessionV2.initializeSession(sessionRecord.getSessionState(),
ourBaseKey, theirBaseKey, ourEphemeralKey,
theirEphemeralKey, ourIdentityKey, theirIdentityKey);
} else {
RatchetingSessionV3.initializeSession(sessionRecord.getSessionState(),
ourBaseKey, theirBaseKey, ourEphemeralKey, theirEphemeralKey,
ourPreKey, theirPreKey, ourIdentityKey, theirIdentityKey);
}
RatchetingSession.initializeSession(sessionRecord.getSessionState(),
preKey.getDeviceKey() == null ? 2 : 3,
ourBaseKey, theirBaseKey, ourEphemeralKey,
theirEphemeralKey, ourPreKey, theirPreKey,
ourIdentityKey, theirIdentityKey);
sessionRecord.getSessionState().setPendingPreKey(preKey.getPreKeyId(), preKey.getDeviceKeyId(), ourBaseKey.getPublicKey());
sessionRecord.getSessionState().setLocalRegistrationId(identityKeyStore.getLocalRegistrationId());
@ -310,10 +306,12 @@ public class SessionBuilder {
sessionRecord.reset();
RatchetingSessionV2.initializeSession(sessionRecord.getSessionState(),
ourBaseKey, message.getBaseKey(),
ourEphemeralKey, message.getEphemeralKey(),
ourIdentityKey, message.getIdentityKey());
RatchetingSession.initializeSession(sessionRecord.getSessionState(),
2,
ourBaseKey, message.getBaseKey(),
ourEphemeralKey, message.getEphemeralKey(),
null, null,
ourIdentityKey, message.getIdentityKey());
sessionRecord.getSessionState().setSessionVersion(message.getVersion());
sessionStore.storeSession(recipientId, deviceId, sessionRecord);

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@ -19,21 +19,22 @@ package org.whispersystems.libaxolotl.ratchet;
import org.whispersystems.libaxolotl.IdentityKey;
import org.whispersystems.libaxolotl.IdentityKeyPair;
import org.whispersystems.libaxolotl.InvalidKeyException;
import org.whispersystems.libaxolotl.state.SessionState;
import org.whispersystems.libaxolotl.ecc.Curve;
import org.whispersystems.libaxolotl.ecc.ECKeyPair;
import org.whispersystems.libaxolotl.ecc.ECPublicKey;
import org.whispersystems.libaxolotl.kdf.DerivedSecrets;
import org.whispersystems.libaxolotl.kdf.HKDF;
import org.whispersystems.libaxolotl.state.SessionState;
import org.whispersystems.libaxolotl.util.Pair;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Arrays;
public class RatchetingSessionV3 {
public class RatchetingSession {
public static void initializeSession(SessionState sessionState,
int sessionVersion,
ECKeyPair ourBaseKey,
ECPublicKey theirBaseKey,
ECKeyPair ourEphemeralKey,
@ -45,17 +46,18 @@ public class RatchetingSessionV3 {
throws InvalidKeyException
{
if (isAlice(ourBaseKey.getPublicKey(), theirBaseKey, ourEphemeralKey.getPublicKey(), theirEphemeralKey)) {
initializeSessionAsAlice(sessionState, ourBaseKey, theirBaseKey, theirEphemeralKey,
initializeSessionAsAlice(sessionState, sessionVersion, ourBaseKey, theirBaseKey, theirEphemeralKey,
ourPreKey, theirPreKey, ourIdentityKey, theirIdentityKey);
} else {
initializeSessionAsBob(sessionState, ourBaseKey, theirBaseKey, ourEphemeralKey,
initializeSessionAsBob(sessionState, sessionVersion, ourBaseKey, theirBaseKey, ourEphemeralKey,
ourPreKey, theirPreKey, ourIdentityKey, theirIdentityKey);
}
sessionState.setSessionVersion(3);
sessionState.setSessionVersion(sessionVersion);
}
private static void initializeSessionAsAlice(SessionState sessionState,
int sessionVersion,
ECKeyPair ourBaseKey, ECPublicKey theirBaseKey,
ECPublicKey theirEphemeralKey,
ECKeyPair ourPreKey, ECPublicKey theirPreKey,
@ -67,7 +69,8 @@ public class RatchetingSessionV3 {
sessionState.setLocalIdentityKey(ourIdentityKey.getPublicKey());
ECKeyPair sendingKey = Curve.generateKeyPair(true);
Pair<RootKey, ChainKey> receivingChain = calculate4DHE(true, ourBaseKey, theirBaseKey,
Pair<RootKey, ChainKey> receivingChain = calculate4DHE(true, sessionVersion,
ourBaseKey, theirBaseKey,
ourPreKey, theirPreKey,
ourIdentityKey, theirIdentityKey);
Pair<RootKey, ChainKey> sendingChain = receivingChain.first().createChain(theirEphemeralKey, sendingKey);
@ -78,6 +81,7 @@ public class RatchetingSessionV3 {
}
private static void initializeSessionAsBob(SessionState sessionState,
int sessionVersion,
ECKeyPair ourBaseKey, ECPublicKey theirBaseKey,
ECKeyPair ourEphemeralKey,
ECKeyPair ourPreKey, ECPublicKey theirPreKey,
@ -88,7 +92,8 @@ public class RatchetingSessionV3 {
sessionState.setRemoteIdentityKey(theirIdentityKey);
sessionState.setLocalIdentityKey(ourIdentityKey.getPublicKey());
Pair<RootKey, ChainKey> sendingChain = calculate4DHE(false, ourBaseKey, theirBaseKey,
Pair<RootKey, ChainKey> sendingChain = calculate4DHE(false, sessionVersion,
ourBaseKey, theirBaseKey,
ourPreKey, theirPreKey,
ourIdentityKey, theirIdentityKey);
@ -96,18 +101,20 @@ public class RatchetingSessionV3 {
sessionState.setRootKey(sendingChain.first());
}
private static Pair<RootKey, ChainKey> calculate4DHE(boolean isAlice,
private static Pair<RootKey, ChainKey> calculate4DHE(boolean isAlice, int sessionVersion,
ECKeyPair ourEphemeral, ECPublicKey theirEphemeral,
ECKeyPair ourPreKey, ECPublicKey theirPreKey,
IdentityKeyPair ourIdentity, IdentityKey theirIdentity)
throws InvalidKeyException
{
try {
byte[] discontinuity = new byte[32];
ByteArrayOutputStream secrets = new ByteArrayOutputStream();
byte[] discontinuity = new byte[32];
ByteArrayOutputStream secrets = new ByteArrayOutputStream();
Arrays.fill(discontinuity, (byte)0xFF);
secrets.write(discontinuity);
if (sessionVersion >= 3) {
Arrays.fill(discontinuity, (byte) 0xFF);
secrets.write(discontinuity);
}
if (isAlice) {
secrets.write(Curve.calculateAgreement(theirEphemeral, ourIdentity.getPrivateKey()));
@ -119,7 +126,7 @@ public class RatchetingSessionV3 {
secrets.write(Curve.calculateAgreement(theirEphemeral, ourEphemeral.getPrivateKey()));
if (ourPreKey != null && theirPreKey != null) {
if (sessionVersion >= 3 && ourPreKey != null && theirPreKey != null) {
secrets.write(Curve.calculateAgreement(theirPreKey, ourPreKey.getPrivateKey()));
}

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@ -1,138 +0,0 @@
/**
* Copyright (C) 2014 Open Whisper Systems
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.whispersystems.libaxolotl.ratchet;
import org.whispersystems.libaxolotl.IdentityKey;
import org.whispersystems.libaxolotl.IdentityKeyPair;
import org.whispersystems.libaxolotl.InvalidKeyException;
import org.whispersystems.libaxolotl.state.SessionState;
import org.whispersystems.libaxolotl.ecc.Curve;
import org.whispersystems.libaxolotl.ecc.ECKeyPair;
import org.whispersystems.libaxolotl.ecc.ECPublicKey;
import org.whispersystems.libaxolotl.kdf.DerivedSecrets;
import org.whispersystems.libaxolotl.kdf.HKDF;
import org.whispersystems.libaxolotl.util.Pair;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
public class RatchetingSessionV2 {
public static void initializeSession(SessionState sessionState,
ECKeyPair ourBaseKey,
ECPublicKey theirBaseKey,
ECKeyPair ourEphemeralKey,
ECPublicKey theirEphemeralKey,
IdentityKeyPair ourIdentityKey,
IdentityKey theirIdentityKey)
throws InvalidKeyException
{
if (isAlice(ourBaseKey.getPublicKey(), theirBaseKey, ourEphemeralKey.getPublicKey(), theirEphemeralKey)) {
initializeSessionAsAlice(sessionState, ourBaseKey, theirBaseKey, theirEphemeralKey,
ourIdentityKey, theirIdentityKey);
} else {
initializeSessionAsBob(sessionState, ourBaseKey, theirBaseKey,
ourEphemeralKey, ourIdentityKey, theirIdentityKey);
}
sessionState.setSessionVersion(2);
}
private static void initializeSessionAsAlice(SessionState sessionState,
ECKeyPair ourBaseKey, ECPublicKey theirBaseKey,
ECPublicKey theirEphemeralKey,
IdentityKeyPair ourIdentityKey,
IdentityKey theirIdentityKey)
throws InvalidKeyException
{
sessionState.setRemoteIdentityKey(theirIdentityKey);
sessionState.setLocalIdentityKey(ourIdentityKey.getPublicKey());
ECKeyPair sendingKey = Curve.generateKeyPair(true);
Pair<RootKey, ChainKey> receivingChain = calculate3DHE(true, ourBaseKey, theirBaseKey, ourIdentityKey, theirIdentityKey);
Pair<RootKey, ChainKey> sendingChain = receivingChain.first().createChain(theirEphemeralKey, sendingKey);
sessionState.addReceiverChain(theirEphemeralKey, receivingChain.second());
sessionState.setSenderChain(sendingKey, sendingChain.second());
sessionState.setRootKey(sendingChain.first());
}
private static void initializeSessionAsBob(SessionState sessionState,
ECKeyPair ourBaseKey, ECPublicKey theirBaseKey,
ECKeyPair ourEphemeralKey,
IdentityKeyPair ourIdentityKey,
IdentityKey theirIdentityKey)
throws InvalidKeyException
{
sessionState.setRemoteIdentityKey(theirIdentityKey);
sessionState.setLocalIdentityKey(ourIdentityKey.getPublicKey());
Pair<RootKey, ChainKey> sendingChain = calculate3DHE(false, ourBaseKey, theirBaseKey,
ourIdentityKey, theirIdentityKey);
sessionState.setSenderChain(ourEphemeralKey, sendingChain.second());
sessionState.setRootKey(sendingChain.first());
}
private static Pair<RootKey, ChainKey> calculate3DHE(boolean isAlice,
ECKeyPair ourEphemeral, ECPublicKey theirEphemeral,
IdentityKeyPair ourIdentity, IdentityKey theirIdentity)
throws InvalidKeyException
{
try {
ByteArrayOutputStream secrets = new ByteArrayOutputStream();
if (isAlice) {
secrets.write(Curve.calculateAgreement(theirEphemeral, ourIdentity.getPrivateKey()));
secrets.write(Curve.calculateAgreement(theirIdentity.getPublicKey(), ourEphemeral.getPrivateKey()));
} else {
secrets.write(Curve.calculateAgreement(theirIdentity.getPublicKey(), ourEphemeral.getPrivateKey()));
secrets.write(Curve.calculateAgreement(theirEphemeral, ourIdentity.getPrivateKey()));
}
secrets.write(Curve.calculateAgreement(theirEphemeral, ourEphemeral.getPrivateKey()));
DerivedSecrets derivedSecrets = new HKDF().deriveSecrets(secrets.toByteArray(),
"WhisperText".getBytes());
return new Pair<RootKey, ChainKey>(new RootKey(derivedSecrets.getCipherKey().getEncoded()),
new ChainKey(derivedSecrets.getMacKey().getEncoded(), 0));
} catch (IOException e) {
throw new AssertionError(e);
}
}
private static boolean isAlice(ECPublicKey ourBaseKey, ECPublicKey theirBaseKey,
ECPublicKey ourEphemeralKey, ECPublicKey theirEphemeralKey)
{
if (ourEphemeralKey.equals(ourBaseKey)) {
return false;
}
if (theirEphemeralKey.equals(theirBaseKey)) {
return true;
}
return isLowEnd(ourBaseKey, theirBaseKey);
}
private static boolean isLowEnd(ECPublicKey ourKey, ECPublicKey theirKey) {
return ourKey.compareTo(theirKey) < 0;
}
}