{"id":43221,"date":"2024-05-14T16:14:03","date_gmt":"2024-05-14T20:14:03","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=43221"},"modified":"2024-05-29T10:36:03","modified_gmt":"2024-05-29T14:36:03","slug":"criticism-of-signal","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2024\/05\/14\/criticism-of-signal\/","title":{"rendered":"Criticism of Signal"},"content":{"rendered":"

Justin Ling<\/a>:<\/p>\n

\n

Zimmermann was a hacker in the oldest sense of the word. In the preceding years, he had grown freaked out by a proposal, put forward by a still-not-young Joe Biden, to force internet companies to give the U.S. government access to their users’ communications.<\/p>\n

Zimmermann knew it was do-or-die time. Either the internet would be a free and open thing, or it would be subject to American meddling and surveillance.<\/p>\n

[…]<\/p>\n

When I first emailed Zimmermann, using an encrypted email client that traces its lineage to PGP, he called me back within an hour: “Do you have Signal?” We moved our conversation to the encrypted app, also a direct descendant of PGP, quickly thereafter.<\/p>\n

[…]<\/p>\n

So imagine my surprise when, this week, I came across a thinly-written essay arguing that Signal had “a problem.” It had, the essay argued, been compromised by the American intelligence state. Not from the outside, but from the inside.<\/p>\n<\/blockquote>\n

I’ve always assumed that it is, because it’s such an important target and the agencies are good at what they do. I haven’t seen any solid evidence (which is what you’d expect if the compromising were done well), but there have been scattered reports suggesting that conversations have been intercepted (though perhaps this was through the phone or the recipients). That said, it’s probably better than the alternatives, and most of us are not government-level targets. As far as I know, Edward Snowden still recommends it.<\/p>\n\n

Matthew Connatser<\/a>:<\/p>\n

Telegram CEO Pavel Durov issued a scathing criticism of Signal, alleging the messaging service is not secure and has ties to US intelligence agencies.<\/p>

There is no evidence Signal is hooked into the US government as described by Durov.<\/p>

[…]<\/p>

“The US government spent $3 million to build Signal’s encryption, and today the exact same encryption is implemented in WhatsApp, Facebook Messenger, Google Messages and even Skype,” the Telegram leader said. “It looks almost as if big tech in the US is not allowed to build its own encryption protocols that would be independent of government interference.”<\/p>

The CEO also claims that users’ Signal messages have popped up in court cases or in the media, and implies that this has happened because the app’s encryption isn’t completely secure. However, Durov cites “important people I’ve spoken to” and doesn’t mention any specific instance of this happening.<\/p><\/blockquote>\n\n

Matthew Green<\/a> (Hacker News<\/a>):<\/p>\n

\n

First things first, Signal Protocol, the cryptography behind Signal (also used in WhatsApp and several other messengers) is open source and has been intensively reviewed by cryptographers. When it comes to cryptography, this is pretty much the gold standard.<\/p>\n

[…]<\/p>\n

One concern with open source code is that even if you review the open code, you don’t know that this code was used to build the app you download from the App Store. “Reproducible builds” let you build the code on your own computer and compare it to the downloaded code.<\/p>\n

Signal has these for Android, and it’s a relatively simple process. Because Android is friendly to this. For various Apple-specific reasons this is shockingly hard to do on iOS. Mostly because apps are encrypted. (Apple should fix this.)<\/p>\n

I want to give Telegram credit because they’ve tried to “hack” a solution for repro builds on iOS. But reading it shows how bad it is: you need a jailbroken (old) iPhone. And at the end you still can’t verify the whole app. Some files stay encrypted.<\/p>\n<\/blockquote>\n\n

josephg<\/a> (2021):<\/p>\n

I spent a few hours trying to get a local build of signal-ios working a few weeks ago, in order to write a PR fix a bug with lost voice messages. The xcode project uses a plethora of device entitlements I’m not allowed to have (since I don’t have the proper signal signing key). Even after a couple hours of tweaking to get it building and deployed to my device, its currently crashing on startup because it can’t access some special signal local device store.<\/p>

You can certainly get your own build working (without notifications and other features). But personally I found it prohibitively difficult to do so.<\/p><\/blockquote>\n\n

Previously:<\/p>\n