No, I don’t mean the new “hack” from Cellebrite, which still seems to make waves1. There’s a more fundamental issue at hand, a result of Signal being secure, not because it’s flawed somehow.

Privacy as Ownership

I’ve been thinking about privacy for a while, if that’s not evident from my recent blog posts. The word is so widely used these days it lost tangible meaning. What does privacy even mean anymore?

To me, privacy is the option to share information. To have a choice. This post I’m writing right now, for example. I can keep it to myself, deep in my journal pages, where it will never be shared. Or I can push it to my repository on GitLab, which will cause Netlify to pull it and build a post on its virtual Hugo environment, with DNS pointing to my domain, for the whole world to see.

In order to have this choice, I first need to own my data. In the old days, I used to have a blog on WordPress.com. There was no local copy; I’d just log into the website, work on my draft, and publish. I never truly owned my data, despite whatever WordPress might say. They could have shut down my account without a second thought, and all of my posts would have been gone forever, no matter how loud I’d yelled. No data ownership, no choice, no privacy2.

Can I Own my Data on Signal…?

At this point, you can see what I’m getting at: with Signal, I don’t own my data. Sure, my conversations are end-to-end encrypted. Sure, no one besides me and the person I’m talking to, not even Signal, can read these conversations. But the WordPress problem I described above still exists: I don’t own the conversation.

Even though the conversation itself is stored locally in a database on my phone, it is fully encrypted (as it should be), and even if I decrypt it (in a similar manner Cellebrite did3, it is still not laid out conveniently. It looks like lines in a table. After all, it’s a database you’re looking at.

As far as I know, Signal doesn’t have the option to export conversations4. To do so would be a security risk for sure, especially for non-informed users who just want to have an encrypted chat client on their phone. However, I believe there’s room for such a feature, perhaps with limited access. Maybe for developers or folks who want to build Signal from source, which I think is still possible (Signal has their repository on Github).

Footnotes

1 If you’re curious if there’s truth in these claims, start by reading Signal’s official response and follow up on Reddit for a few entertaining remarks.

2 You could argue that having my post hosted on GitLab is not much different than WordPress, and you’d be right, with one important exception: all my posts are local before they ever get pushed to GitLab. GitLab, and the post you’re now reading, are just a copy of my original content, which I do my best to preserve with encrypted backups. If GitLab closes my account tomorrow, I won’t lose anything. I could probably relocate to a new repository within the same day.

3 The retracted blog post on their site showed how they decrypted the local database on an Android device. In a way, it was pretty informative. The big problem with it was that it was no hack at all: they described a way to decrypt the information using an unlocked phone. The equivalent of breaking into a house after you have already unlocked the front door with the key you happen to have.

4 There’s an option to creak a local encrypted backup, but this backup is meant to be used with Signal. If you don’t have Signal, you can’t use this option.