Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/10/interview-with-signals-new-president.html
Long and interesting interview with Signal’s new president, Meredith Whittaker:
WhatsApp uses the Signal encryption protocol to provide encryption for its messages. That was absolutely a visionary choice that Brian and his team led back in the day - and big props to them for doing that. But you can’t just look at that and then stop at message protection. WhatsApp does not protect metadata the way that Signal does. Signal knows nothing about who you are. It doesn’t have your profile information and it has introduced group encryption protections. We don’t know who you are talking to or who is in the membership of a group. It has gone above and beyond to minimize the collection of metadata.
WhatsApp, on the other hand, collects the information about your profile, your profile photo, who is talking to whom, who is a group member. That is powerful metadata. It is particularly powerful—and this is where we have to back out into a structural argument for a company to collect the data that is also owned by Meta/Facebook. Facebook has a huge amount, just unspeakable volumes, of intimate information about billions of people across the globe.
It is not trivial to point out that WhatsApp metadata could easily be joined with Facebook data, and that it could easily reveal extremely intimate information about people. The choice to remove or enhance the encryption protocols is still in the hands of Facebook. We have to look structurally at what that organization is, who actually has control over these decisions, and at some of these details that often do not get discussed when we talk about message encryption overall.
I am a fan of Signal and I use it every day. The one feature I want, which WhatsApp has and Signal does not, is the ability to easily export a chat to a text file.
Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/08/signal-phone-numbers-exposed-in-twilio-hack.html
Twilio was hacked earlier this month, and the phone numbers of 1,900 Signal users were exposed:
Here’s what our users need to know:
- All users can rest assured that their message history, contact lists, profile information, whom they’d blocked, and other personal data remain private and secure and were not affected.
- For about 1,900 users, an attacker could have attempted to re-register their number to another device or learned that their number was registered to Signal. This attack has since been shut down by Twilio. 1,900 users is a very small percentage of Signal’s total users, meaning that most were not affected.
We are notifying these 1,900 users directly, and prompting them to re-register Signal on their devices.
If you were not notified, don’t worry about it. But it does bring up the old question: Why does Signal require a phone number to use? It doesn’t have to be that way.
Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/12/cellebrite-can-break-signal.html
Cellebrite announced that it can break Signal. (Note that the company has heavily edited its blog post, but the original — with lots of technical details — was saved by the Wayback Machine.)
News article. Slashdot post.
The whole story is puzzling. Cellebrite’s details will make it easier for the Signal developers to patch the vulnerability. So either Cellebrite believes it is so good that it can break whatever Signal does, or the original blog post was a mistake.
EDITED TO ADD (12/22): Signal’s Moxie Marlinspike takes serious issue with Cellebrite’s announcement. I have urged him to write it up, and will link to it when he does.
EDITED TO ADD (12/23): I need to apologize for this post. I finally got the chance to read all of this more carefully, and it seems that all Cellebrite is doing is reading the texts off of a phone they can already access. To this has nothing to do with Signal at all. So: never mind. False alarm. Apologies, again.