WhisperSystems/TextSecure — pull request #1768 by mcginty (2014-07-31 00:40:55+00:00)
Title: New encrypted export

* switch to xstream for serialization and deserialization
* use our own custom file format for encrypted backups

file format:
```
4 byte header length
header (serialized EncryptedBackupHeader protobuf)
encrypted xml contents with messages and identity key
```