Comment by dijit
19 hours ago
The standard threat model for secure messaging does assume a potentially compromised provider.. that’s exactly why the client-trust issue matters.
If the provider is compromised (maliciously or via hack/subpoena), they can alter the client to capture data before E2EE engages, rendering it moot.
E2EE protects past messages from server-side access, sure, but it doesn’t prevent future compromises via client backdoors, which are a real vector under laws like Australia’s TOLA or US CLOUD Act, again: providers have been compelled to modify software (e.g., Lavabit’s resistance led to shutdown, but others comply quietly).
You’re right that client-server alone fails catastrophically on server compromise, but E2EE isn’t a panacea if the same actor controls the client supply chain.
Trust is binary: If you don’t trust the provider, don’t use their client. reproducible builds help a tiny fraction, but for most, it’s unverifiable.
In partial-trust scenarios (e.g., worrying about hacks but not full malice), client-server with distributed keys and TLS can suffice without E2EE’s complexities.
I’m hand-waving a bit here; but I’m talking about peoples actual realities, not some hypothetical.
How does E2EE hold up if a subpoena forces a silent client update? You won’t know, and history shows that’s the path of least resistance for adversaries.
Client supply chain is moot in the client-server setting. The attackers just target the server and get everything. You only get to raise the salience of the client supply chain when E2EE is already in place. Again: this is an analysis specific to secure messaging.
Slack isn't E2EE secure. The Slack client supply chain is not how I worry about my Slack message history being intercepted.
Re: Slack; yeah, that’s not apples-to-apples for secure 1:1 messaging (it’s enterprise group chat with admins often having god-mode access anyway).
A better comp might be old-school Skype pre-Microsoft: client-server backbone (after ditching full P2P), tight client/network control, no E2EE, yet no major leaks despite heavy scrutiny.
It worked for millions in a “good enough” threat model without pretending to be bulletproof. Secure messaging apps that default to client-server (like Telegram’s non-secret chats) are similar. They pay lip service to groups but prioritise 1:1, and the security theatre of optional E2EE doesn’t change the core trust calculus.
If you don’t trust the provider, don’t trust their code. Simple as.
The security model of Telegram is essentially that of Slack, plus a seldom-used direct E2EE messenger. You literally can't trust Slack or Telegram. You can opt not to trust Signal; I don't care. But it's at least an option.
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