/**
* Takes a byte array containing serialized and concatenated MPIs and converts it to an array of
* MPIs. The buffer is assumed to consist of a 4-byte int containing the number of MPIs in the
* array, followed by {size, data} pairs for each MPI.
*
* @throws OTRException
*/
public static MPI[] unserializeMPIArray(byte[] buffer) throws OTRException {
InBuf ibuf = new InBuf(buffer);
int count = (int) ibuf.readUInt();
if (count <= 0) throw new OTRException("Invalid count");
MPI[] mpis = new MPI[count];
for (int i = 0; i < count; i++) {
mpis[i] = MPI.readMPI(ibuf);
}
return mpis;
}
/** Hash one or two MPIs. To hash only one MPI, b may be set to NULL. */
public static MPI hash(int version, MPI a, MPI b, Provider prov) throws OTRException {
int totalsize = 1 + 4 + a.getLength();
if (b != null) {
totalsize += 4 + b.getLength();
}
byte[] buf = new byte[totalsize];
OutBuf obuf = new OutBuf(buf);
obuf.writeByte((byte) version);
obuf.writeUInt(a.getLength());
a.writeRaw(obuf);
if (b != null) {
obuf.writeUInt(b.getLength());
b.writeRaw(obuf);
}
byte[] out = obuf.getBytes();
SHA256 sha = prov.getSHA256();
byte[] digest = sha.hash(out);
return new MPI(digest);
}
void goEncrypted(OTRCallbacks callback) throws OTRException {
// See if we're talking to ourselves
byte[] theiry = auth.their_pub.serialize();
byte[] their_trim = new byte[theiry.length - 4];
System.arraycopy(theiry, 4, their_trim, 0, their_trim.length);
byte[] oury = auth.our_dh.getPublicKey().serialize();
byte[] our_trim = new byte[oury.length - 4];
System.arraycopy(oury, 4, our_trim, 0, our_trim.length);
if (prov.compareMPI(new MPI(their_trim), new MPI(our_trim)) == 0) {
// Yes, we are.
callback.handleMsgEvent(OTRCallbacks.OTRL_MSGEVENT_MSG_REFLECTED, this, null);
throw new OTRException("Message reflected");
}
// Find the fingerprint
FingerPrint found_print = this.findFingerPrint(auth.their_fingerprint, true, callback);
/* Is this a new session or just a refresh of an existing one? */
if (this.msgState.getCurState() == MsgState.ST_ENCRYPTED
&& Util.arrayEquals(this.activeFingerprint.fingerPrint, found_print.fingerPrint)
&& this.our_keyid - 1 == this.auth.our_keyid
&& prov.compareMPI(
MPI.readMPI(new InBuf(this.our_old_dh_key.getPublicKey().serialize())),
MPI.readMPI(new InBuf(this.auth.our_dh.getPublicKey().serialize())))
== 0
&& ((this.their_keyid > 0
&& this.their_keyid == auth.their_keyid
&& prov.compareMPI(
MPI.readMPI(new InBuf(this.their_y.serialize())),
MPI.readMPI(new InBuf(this.auth.their_pub.serialize())))
== 0)
|| (this.their_keyid > 1
&& this.their_keyid - 1 == this.auth.their_keyid
&& this.their_old_y != null
&& prov.compareMPI(
MPI.readMPI(new InBuf(this.their_y.serialize())),
MPI.readMPI(new InBuf(this.auth.their_pub.serialize())))
== 0))) {
/* This is just a refresh of the existing session. */
callback.stillSecure(this, auth.initiated);
ignore_message = 1;
return;
}
// Copy the information from the auth into the context
System.arraycopy(auth.secure_session_id, 0, this.sessionId, 0, 20);
this.sessionid_len = auth.sessionid_len;
// Copy the keys
this.their_keyid = auth.their_keyid;
this.their_y = auth.their_pub;
this.their_old_y = null;
if (our_keyid - 1 != auth.our_keyid) {
this.our_old_dh_key = auth.our_dh;
this.our_dh_key = prov.getDHKeyPairGenerator().generateKeyPair();
this.our_keyid = auth.our_keyid + 1;
}
// Create the session keys from the DH keys
this.sesskeys[0][0] = new DHSesskeys(prov);
this.sesskeys[1][0] = new DHSesskeys(prov);
this.sesskeys[0][0].computeSession(this.our_dh_key, this.their_y);
this.sesskeys[1][0].computeSession(this.our_old_dh_key, this.their_y);
this.generation++;
this.activeFingerprint = found_print;
int oldstate = msgState.getCurState();
msgState.processEvent(MsgState.EVT_AUTHENTICATED);
callback.updateContextList();
if (oldstate == MsgState.ST_ENCRYPTED
&& Util.arrayEquals(this.activeFingerprint.fingerPrint, found_print.fingerPrint)) {
callback.stillSecure(this, this.auth.initiated);
} else {
callback.goneSecure(this);
}
this.gone_encrypted = 1;
}