1) Change SessionBuilder to only establish sessions via
KeyExchangeMessage and PreKeyBundles.
2) Change SessionCipher to decrypt either WhisperMessage
or PreKeyWhisperMessage items, automatically building
a session for the latter.
3) Change SessionCipher to tear down new sessions built
with PreKeyWhisperMessages if the embedded WhsiperMessage
fails to decrypt.
1) Use the new /v2/keys API for storing/retrieving prekey bundles.
2) For sessions built with PreKeyBundle and PreKeyWhisperMessage,
use a v3 ratcheting session when available.
1) Add plain two-way key exchange support libaxolotl by moving
all the KeyExchangeMessage code there.
2) Move the bulk of KeyExchangeProcessor code to libaxolotl
for setting up sessions based on retrieved prekeys, received
prekeybundles, or exchanged key exchange messages.
1) Break the core cryptography functions out into libaxolotol.
2) The objective for this code is a Java library that isn't
dependent on any Android functions. However, while the
code has been separated from any Android functionality,
it is still an 'android library project' because of the
JNI.
1) On the push side, this message is a flag in PushMessageContent.
Any secure message with that flag will terminate the current
sessin.
2) On the SMS side, there is an "end session" wire type and
the convention that a message with this wire type must be
secure and contain the string "TERMINATE."
1) In addition to the Recipient interface, there is now
RecipientDevice. A Recipient can have multiple corresponding
RecipientDevices. All addressing is done to a Recipient, but
crypto sessions and transport delivery are done to
RecipientDevice.
2) The Push transport handles the discovery and session setup
of additional Recipient devices.
3) Some internal rejiggering of Groups.
1) Added SMS transport support.
2) Keep track of whether a PreKeyBundle message has gotten
a response, and send them as subsequent messages until
one has been received.
1) Move all the crypto classes from securesms.crypto.
2) Move all the crypto storage from securesms.database.keys
3) Replace the old imported BC code with spongycastle.
1) There is no longer a concept of "verified" or "unverified."
Only "what we saw last time" and "different from last time."
2) Let's eliminate "verify session," since we're all about
identity keys now.
3) Mark manually processed key exchanges as processed.
1) We now try to hand out cursors at a minimum. There has always been
a fairly clean insertion layer that handles encrypting message bodies,
but the process of decrypting message bodies has always been less than
ideal. Here we introduce a "Reader" interface that will decrypt message
bodies when appropriate and return objects that encapsulate record state.
No more MessageDisplayHelper. The MmsSmsDatabase interface is also more
sane.
2) We finally rid ourselves of the technical debt associated with TextSecure's
initial usage of the default SMS DB. In that world, we weren't able to use
anything other than the default "Inbox, Outbox, Sent" types to describe a
message, and had to overload the message content itself with a set of
local "prefixes" to describe what it was (encrypted, asymetric encrypted,
remote encrypted, a key exchange, procssed key exchange), and so on.
This includes a major schema update that transforms the "type" field into
a bitmask that describes everything that used to be encoded in a prefix,
and prefixes have been completely eliminated from the system.
No more Prefix.java
3) Refactoring of the MultipartMessageHandler code. It's less of a mess, and
hopefully more clear as to what's going on.
The next step is to remove what we can from SmsTransportDetails and genericize
that interface for a GCM equivalent.
