mirror of
https://github.com/vanitasvitae/Smack.git
synced 2024-11-27 22:42:06 +01:00
44 lines
2 KiB
Markdown
44 lines
2 KiB
Markdown
|
Migrating smack-omemo from 4.2.1 to 4.x.x
|
||
|
|
=========================================
|
||
|
|
|
||
|
|
The implementation of smack-omemo and smack-omemo-signal was originally started as an
|
||
|
|
academic project under pressure of time.
|
||
|
|
For that reason, the API was not perfect when OMEMO support was first introduced in
|
||
|
|
Smack in version 4.2.1.
|
||
|
|
Many issues of smack-omemo have been resolved over the course of the last year in
|
||
|
|
a major effort, which is why smack-omemo and smack-omemo-signalwere excluded from
|
||
|
|
the 4.2.2 release.
|
||
|
|
|
||
|
|
During this time major parts of the implementation were redone and the API changed
|
||
|
|
as a consequence of that. This guide will go through all notable changes in order
|
||
|
|
to make the process of upgrading as easy and straight forward as possible.
|
||
|
|
|
||
|
|
## Trust
|
||
|
|
One major change is, that the OmemoStore implementations no longer store trust decisions.
|
||
|
|
Methods related to trust have been removed from OmemoStore implementations.
|
||
|
|
Instead the client is now responsible to store those.
|
||
|
|
Upon startup, the client now must pass an `OmemoTrustCallback` to the `OmemoManager`
|
||
|
|
which is used to access and change trust decisions.
|
||
|
|
|
||
|
|
It is recommended for the client to store trust decisions as tuples of (omemo device,
|
||
|
|
fingerprint of identityKey, trust state).
|
||
|
|
When querying a trust decision (aka. "Is this fingerprint trusted for that device?),
|
||
|
|
the local fingerprint should be compared to the provided fingerprint.
|
||
|
|
|
||
|
|
The method signatures for setting and querying trust from inside the OmemoManager are
|
||
|
|
still the same. Internally they access the `OmemoTrustCallback` set by the client.
|
||
|
|
|
||
|
|
## Encryption
|
||
|
|
Message encryption in smack-omemo 4.2.1 was ugly. Encryption for multiple devices
|
||
|
|
could fail because session negotiation could go wrong, which resulted in an
|
||
|
|
exception, which contained all devices with working sessions.
|
||
|
|
That exception could then be used in
|
||
|
|
`OmemoManager.encryptForExistingSessions(CannotEstablishOmemoSessionException exception, String message)`,
|
||
|
|
to encrypt the message for all devices with a session.
|
||
|
|
|
||
|
|
The new API is
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|