package com.securecomcode.text.crypto.protocol;
import com.google.protobuf.ByteString;
import com.google.protobuf.InvalidProtocolBufferException;
import org.whispersystems.textsecure.crypto.IdentityKey;
import org.whispersystems.textsecure.crypto.InvalidKeyException;
import org.whispersystems.textsecure.crypto.InvalidMessageException;
import org.whispersystems.textsecure.crypto.InvalidVersionException;
import org.whispersystems.textsecure.crypto.LegacyMessageException;
import org.whispersystems.textsecure.crypto.ecc.Curve;
import org.whispersystems.textsecure.crypto.ecc.ECPublicKey;
import org.whispersystems.textsecure.crypto.protocol.CiphertextMessage;
import org.whispersystems.textsecure.crypto.protocol.WhisperProtos;
import org.whispersystems.textsecure.util.Base64;
import org.whispersystems.textsecure.util.Conversions;
import org.whispersystems.textsecure.util.Util;
import java.io.IOException;
public class KeyExchangeMessageV2 extends KeyExchangeMessage {
public static final int INITIATE_FLAG = 0x01;
public static final int RESPONSE_FLAG = 0X02;
public static final int SIMULTAENOUS_INITIATE_FLAG = 0x04;
private final int version;
private final int supportedVersion;
private final int sequence;
private final int flags;
private final ECPublicKey baseKey;
private final ECPublicKey ephemeralKey;
private final IdentityKey identityKey;
private final byte[] serialized;
public KeyExchangeMessageV2(int sequence, int flags,
ECPublicKey baseKey, ECPublicKey ephemeralKey,
IdentityKey identityKey)
{
this.supportedVersion = CiphertextMessage.CURRENT_VERSION;
this.version = CiphertextMessage.CURRENT_VERSION;
this.sequence = sequence;
this.flags = flags;
this.baseKey = baseKey;
this.ephemeralKey = ephemeralKey;
this.identityKey = identityKey;
byte[] version = {Conversions.intsToByteHighAndLow(this.version, this.supportedVersion)};
byte[] message = WhisperProtos.KeyExchangeMessage.newBuilder()
.setId((sequence << 5) | flags)
.setBaseKey(ByteString.copyFrom(baseKey.serialize()))
.setEphemeralKey(ByteString.copyFrom(ephemeralKey.serialize()))
.setIdentityKey(ByteString.copyFrom(identityKey.serialize()))
.build().toByteArray();
this.serialized = Util.combine(version, message);
}
public KeyExchangeMessageV2(String serializedAndEncoded)
throws InvalidMessageException, InvalidVersionException, LegacyMessageException
{
try {
byte[] serialized = Base64.decodeWithoutPadding(serializedAndEncoded);
byte[][] parts = Util.split(serialized, 1, serialized.length - 1);
this.version = Conversions.highBitsToInt(parts[0][0]);
this.supportedVersion = Conversions.lowBitsToInt(parts[0][0]);
if (this.version <= CiphertextMessage.UNSUPPORTED_VERSION) {
throw new LegacyMessageException("Unsupported legacy version: " + this.version);
}
if (this.version > CiphertextMessage.CURRENT_VERSION) {
throw new InvalidVersionException("Unknown version: " + this.version);
}
WhisperProtos.KeyExchangeMessage message = WhisperProtos.KeyExchangeMessage.parseFrom(parts[1]);
if (!message.hasId() || !message.hasBaseKey() ||
!message.hasEphemeralKey() || !message.hasIdentityKey())
{
throw new InvalidMessageException("Some required fields missing!");
}
this.sequence = message.getId() >> 5;
this.flags = message.getId() & 0x1f;
this.serialized = serialized;
this.baseKey = Curve.decodePoint(message.getBaseKey().toByteArray(), 0);
this.ephemeralKey = Curve.decodePoint(message.getEphemeralKey().toByteArray(), 0);
this.identityKey = new IdentityKey(message.getIdentityKey().toByteArray(), 0);
} catch (InvalidProtocolBufferException e) {
throw new InvalidMessageException(e);
} catch (InvalidKeyException e) {
throw new InvalidMessageException(e);
} catch (IOException e) {
throw new InvalidMessageException(e);
}
}
@Override
public int getVersion() {
return version;
}
public ECPublicKey getBaseKey() {
return baseKey;
}
public ECPublicKey getEphemeralKey() {
return ephemeralKey;
}
@Override
public IdentityKey getIdentityKey() {
return identityKey;
}
@Override
public boolean hasIdentityKey() {
return true;
}
@Override
public int getMaxVersion() {
return supportedVersion;
}
public boolean isResponse() {
return ((flags & RESPONSE_FLAG) != 0);
}
public boolean isInitiate() {
return (flags & INITIATE_FLAG) != 0;
}
public boolean isResponseForSimultaneousInitiate() {
return (flags & SIMULTAENOUS_INITIATE_FLAG) != 0;
}
public int getFlags() {
return flags;
}
public int getSequence() {
return sequence;
}
public String serialize() {
return Base64.encodeBytesWithoutPadding(serialized);
}
}