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Web-based cryptography is always snake oil

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Re: Web-based cryptography is always snake oil

#91

Post by charcircuit »

crote wrote: post #44
bigfatkitten wrote: post #22

Earlier quoted context omitted.

One thing you can do is have your adversary put their money where their mouth is and use the very same products, sourced independently, that they use to protect their own sensitive information. There are limits to this of course. You can’t buy a TACLANE[1], but you can buy many of the other products[2] USG uses to protect its own classified information. [1] https://gdmissionsystems.com/encryption/taclane-network-encr…

The obvious counterexample is NOBUS[0] vulnerabilities, and intentional backdoors like the Clipper Chip[1] or Dual_EC_DRBG[2]: if you genuinely believe you are the only one who could possibly exploit it, there's no reason to avoid using it. A more modern example is probably the NSA aggressively pushing[3] for replacing classical encryption with post-quantum encryption, rather than taking the more conservative and pro…

>Dual_EC_DRBG

There is no hard evidence that it was backdoored.

Re: Web-based cryptography is always snake oil

#93

Post by delusional »

tptacek wrote: post #84
delusional wrote: post #81

Earlier quoted context omitted.

> Using e2e from a US-based entity means you are prone to spying from the US government, but at least you know you're reasonably secure against the IRGC, the Chinese intelligence service, the FSB, and so on. Framing this in terms of governmental espionage is nonsensical. Using e2e from a US-based entity makes you completely sure that the US government is spying on you, because they assert direct control over the soft…

I think the whole US vs. non-US thing is total crap and there's nothing you can reasonably do with it in any direction, but I always think it's important to point out that US signals intelligence can lawfully compromise foreign communications; that's literally their chartered purpose.

> there's nothing you can reasonably do with it in any direction

I wholeheartedly agree. That's why bringing nation state threats into these kinds of discussions is so pointless. If you want security from governments, the amount of security work you have to do is so far beyond what any reasonable person is willing to endure that it makes no sense to talk about on hackernews. That stuff is for real professional discussions at real professional congresses.

Re: Web-based cryptography is always snake oil

#94

Post by chr15m »

> the code which implements a client-side web application is distributed by the given website

Incorrect, and trivially falsifiable. Examples:

- Self hosting, where you control both client and server.

- Loading a web app from file:///

- Loading a web app from localhost.

The author's "no exceptions" is simply wrong.

The author also seems to assume the same server is required to both serve the code and store/transmit encrypted messages which obviously isn't the case. In addition the statements about service workers are ignorant.

The rest of the analysis is largely correct and the threat outlined (where somebody can replace your client) is a serious one that many underestimate. In particular the proprietary native mobile app model is vulnerable to this, as mentioned.

Re: Web-based cryptography is always snake oil

#95

Post by bloppe »

memoriyato3 wrote: post #7
somezero wrote: post #4

The entire argument is based on the definition of an “Incoherent cryptosystem”, which is too restrictive to be useful for cases that you want eg. Tor is also developed and distributed by Tor people and it is supposed to protect you against everyone, including the Tor people.

technically you could audit your local copy of tor source code, build it, and then never upgrade it. still this wouldn't guarantee that all the other nodes are not compromised

You could also audit the JavaScript / Wasm that's running in your browser. In fact, a security-focused e2e application might want to purposely keep all client-side code un-minified and highly readable for this very purpose, but decompilers and LLMs could provide reasonable auditability regardless

Re: Web-based cryptography is always snake oil

#98

Post by tarpitt »

stymaar wrote: post #65
xg15 wrote: post #64

Earlier quoted context omitted.

But that's OP's point. If the server is pwned, the hackers can simply change the front-end of the app and have it send the confidential data to wherever after it was decrypted on the client.

See what I wrote above: > in practice “the attacker is able to deploy arbitrary code on your behalf for an extended period of time without being detected ” is a much narrower attack surface than “the attacker is able to obtain read-only access to your DB or your backups for at least a few minutes”. In the former case, the encryption being broken is also the least of your concern, as you've basically given remote acce…

I would say that they are snake oil because of that. Data breaches occur more often than rootkits because most developers see that this path adding easily-removable encryption does nothing in the long run.

Re: Web-based cryptography is always snake oil

#99

Post by tarpitt »

stymaar wrote: post #61
upofadown wrote: post #53

Earlier quoted context omitted.

But claiming that your system is end to end encrypted means that you are claiming protection from you and your system. This is mainly a truth in advertising issue.

> means that you are claiming protection from you and your system. Not necessarily. I push for e2ee everywhere I can for a completely different reason: when (not “if”, “when“) we get breached, we cannot leak sensitive data we don't have.

The problem is that your system can be changed at any time such that you can have the information.

Re: Web-based cryptography is always snake oil

#100

Post by tarpitt »

sscaryterry wrote: post #39
adirelle wrote: post #37

Earlier quoted context omitted.

> the entity you want protection against is generally not the software provider but a third party. This. The author is dismissing the whole web-based cryptography, or any end-to-end cryptography for that matter, on the basis of a one-dimension analysis.

The article is nothing but a rant.

Your comment is merely a comment and not an argument
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