ContactDiscoveryService VS whatsapp-viewer

[1] https://signal.org/blog/private-contact-discovery/

Signal uses SGX for remote attestation, which presumably lets the client verify that the code running on the server is a build of the OSS code and not a modified version. But I don't know the details or if this is reliable.

SGX and remote attestation described here:

https://signal.org/blog/private-contact-discovery/

Signal does private contact discovery and the effort they've gone to to do this is quite impressive.

TEEs have numerous privacy-enhancing applications that may benefit users. One of them is, as discussed earlier, private contact discovery; the Signal application uses a contact discovery service enhanced using Intel SGX, a TEE technology, to protect its users' privacy. A similar application of TEEs is performing malware analysis in a remote cloud service, so that the service may not identify users by the contents of their devices, such as the applications they have installed, especially important as 98.93% of users may be uniquely identified by the list of applications they have installed.

Signal (or, more accurately, one of its predecessors) used to use client-side private set intersection for contact discovery, but this scales poorly [1].

Now they use a solution based on Intel SGX and server-side trusted computing [2].

[1] https://signal.org/blog/contact-discovery/

[2] https://signal.org/blog/private-contact-discovery/

Already tied whatsapp viewer (https://github.com/andreas-mausch/whatsapp-viewer) but it shows db file version too old to be read.

This method is a bit dangerous, since it uses ADB and may brick your phone and also corrupt your history. I made sure I had all my chats backed up before try it for the first time. It worked, then I used again yesterday and it worked again. Cant be sure that it will work on your device, but if you want to give it a try, here is what I did Backuping whatsapp chat history without root: I used these tools back in september 2022 and worked just fine. To extract the key and uncrypted messages database: https://github.com/YuvrajRaghuvanshiS/WhatsApp-Key-Database-Extractor To decrypt the backup databases using the key you extracted and also to visualize the databases: https://github.com/andreas-mausch/whatsapp-viewer/releases To fix the SQL tables in order to visualize in the WhatsApp-Viewer: https://github.com/andreas-mausch/whatsapp-viewer/issues/151#issuecomment-1229244368

Whatsapp Viewer app on GitHub

The result is a sqlite database that can be dumped or browsed with the regular (database) tools; there are 2 projects I know of that are actually reading the data and presenting it nicely but both are broken just now as Whatsapp changed the name of some tables (the changes are only cosmetic, the data is still there): https://github.com/B16f00t/whapa and https://github.com/andreas-mausch/whatsapp-viewer .

(11) [Optionally:] If you want to send a message to a group instead of a single contact, you will need the precise jid number of this group. You can get it with the help of Whatsapp Viewer program.

The only way to cope with this is really ever-increasing storage on the phone (mind the sub please!) but otherwise export the conversation (I'm talking from some program that can read the db, again, major nuisance as the chats are encrypted and you don't have the key!!!) and possibly parse that to identify all the linked media from there.