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NSA-proof encryption exists. Why doesn’t anyone use it?

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Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#41

Post by kniht »

aasarava wrote: post #26
kniht wrote: post #18

Earlier quoted context omitted.

If you're doing public key crypto on the client side in javascript, then the client side JS must necessarily have access to the private key (unless you have a TPM _and_ browser hooks to use it). This means that suddenly the private key is vulnerable to any XSS attacker that can inject itself into the same origin as your javascript crypto code.

Fair point. XSS likely wouldn't be a problem in the case of a desktop email client. But in the case of a Gmail or Outlook.com frontend, I can see how you would be concerned about something in the js served up by Google or MS capturing the private key and sending it to the server. That said, couldn't this be mitigated by having a strong passphrase on the private key? How hard is the wrapper to attack? Also, couldn't s…

AFAIK a strong key passphrase would be effective at protecting the private key while it's at rest (stolen laptop / hard drive). However as soon as the private key is pulled into memory for a signing or encryption operation the passphrase doesn't matter as the raw key is needed at that point.

As for your second question, there are techniques that perform static and dynamic analysis on javascript to try and detect illegal flows or taint propagation (without having to resort to monitoring the outbound network traffic). See [1] and [2] if you're interested in that topic.

[1] http://static.usenix.org/event/sec10/tech/full_papers/Bandha... [2] http://publik.tuwien.ac.at/files/pub-inf_5310.pdf

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#42

Post by kimlelly »

glurgh wrote: post #31
kimlelly wrote: post #17

Earlier quoted context omitted.

Can you back these calculations up with a known scientific source?

Sure. A 128 bit key is 2^128 or 3.4e38. Numbers about total world computing power (most of it probably stuck in GPUs doing windows animations and playing Call of Duty) bandied about are in the Ne18ish ops/sec range, age of the universe is in the 4e17 range. And I have a great deal of margin by treating a 'decrypt and verify' operation as a 'basic operation' and using a completely preposterous time period like the age…

Thanks, that helps!

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#43

Post by aroch »

tsahyt wrote: post #33
david_shaw wrote: post #25

> NSA-proof encryption exists. Yup. Except it's not that easy. Let's say that you're using OTR to provide very strong end-to-end encryption for a conversation between yourself and a buddy, Bob. Maybe he's in a hostile area, and you're worried that if his government sniffs his traffic, that he could be executed for speaking to Americans. Data in transit that is intercepted, if configured correctly, is almost certainly…

Weren't there cases of the government forcing people to give them their passphrase in the US already? Somehow I seem to remember something like this very vaguely.

You're probably thinking about the child pornography case that's going on right now where the accused was ordered by the courts to provide his passphrase. Higher level courts say you cannot compel that sort of evidence.

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#44

Post by kimlelly »

glurgh wrote: post #38
kimlelly wrote: post #23

Earlier quoted context omitted.

@aryastark - What's the nature of AES 128 & Co., meaning: Who can and cannot discover flaws? Is this like open source where the whole world can watch or is this somehow a closed thing like Windows, MacOS, etc.?

These are openly available, highly reviewed algorithms - their adoption as standards, too, is done by a process of open competition. And it's probably safe to say that the amount of research and analysis being done on them in the open exceeds that done in secret by government agencies by a wide margin.

Thanks, very important to know!

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#45

Post by ohazi »

rollo_tommasi wrote: post #27
pavel_lishin wrote: post #5

Earlier quoted context omitted.

And if it is stored client-side, what happens when the user inevitably loses their key? You and I might have backups in multiple places, and on an encrypted USB stick in a bank vault, but my dad doesn't, and the next time he spills wine on his laptop, there goes literally all of his e-mail.

Why not simply make the cryptographically secure service opt-in?

This is the real reason why cryptography hasn't caught on. It's opt-in by nature - No matter how hard you try, you can't send someone an encrypted message if they don't have a public key for you to use.

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#46

Post by __alexs »

tsahyt wrote: post #33
david_shaw wrote: post #25

> NSA-proof encryption exists. Yup. Except it's not that easy. Let's say that you're using OTR to provide very strong end-to-end encryption for a conversation between yourself and a buddy, Bob. Maybe he's in a hostile area, and you're worried that if his government sniffs his traffic, that he could be executed for speaking to Americans. Data in transit that is intercepted, if configured correctly, is almost certainly…

Weren't there cases of the government forcing people to give them their passphrase in the US already? Somehow I seem to remember something like this very vaguely.

In the UK Oliver Drage (alleged child pornographer) was convicted and jailed for 16 weeks under RIPA for not disclosing his password. http://www.newstatesman.com/blogs/the-staggers/2010/10/polic...

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#47

Post by Xcelerate »

cube13 wrote: post #36
lordgilman wrote: post #30

Earlier quoted context omitted.

This has come up in the past on HN. As I understand it the newspaper story is bull. As for advancements in technology the answer is likely no - producing that technology requires an entire toolchain/industry that the NSA is unlikely to replicate with its size. The only shot the NSA has at pulling ahead of us is with entirely mathematical things like crypto (which they did at least in the 70s with differential cryptan…

>This has come up in the past on HN. As I understand it the newspaper story is bull. Pretty much. The same effect that causes stars to twinkle limits the resolution of space-based spy satellites imagery of the ground. http://en.wikipedia.org/wiki/Astronomical_seeing

That's for distant stars though, isn't it? I mean, just with Google Maps you can see the mirrors on a car. Newsprint isn't that much of a step up.

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#48

Post by JulianMorrison »

david_shaw wrote: post #25

> NSA-proof encryption exists. Yup. Except it's not that easy. Let's say that you're using OTR to provide very strong end-to-end encryption for a conversation between yourself and a buddy, Bob. Maybe he's in a hostile area, and you're worried that if his government sniffs his traffic, that he could be executed for speaking to Americans. Data in transit that is intercepted, if configured correctly, is almost certainly…

One thing widespread encryption would do is make it impossible for the NSA to just slurp the combined textual output of humanity into hadoop and mapreduce over it.

They can use "hitting the suspect with a wrench" cryptanalysis on a solo victim, but not on a crowd.

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#49

Post by tlrobinson »

david_shaw wrote: post #25

> NSA-proof encryption exists. Yup. Except it's not that easy. Let's say that you're using OTR to provide very strong end-to-end encryption for a conversation between yourself and a buddy, Bob. Maybe he's in a hostile area, and you're worried that if his government sniffs his traffic, that he could be executed for speaking to Americans. Data in transit that is intercepted, if configured correctly, is almost certainly…

Ah, the old rubber-hose cryptanalysis https://en.wikipedia.org/wiki/Rubber-hose_cryptanalysis

However, according to https://en.wikipedia.org/wiki/Perfect_forward_secrecy OTR does provide "perfect forward secrecy as well as deniable encryption". Doesn't that provide some protection against rubber-hose cryptanalysis?

Re: NSA-proof encryption exists. Why doesn’t anyone use it?

#50

Post by silvestrov »

david_shaw wrote: post #25

> NSA-proof encryption exists. Yup. Except it's not that easy. Let's say that you're using OTR to provide very strong end-to-end encryption for a conversation between yourself and a buddy, Bob. Maybe he's in a hostile area, and you're worried that if his government sniffs his traffic, that he could be executed for speaking to Americans. Data in transit that is intercepted, if configured correctly, is almost certainly…

There's no need to throw him in jail. They can just install a hidden camera and record him typing the password. Next time he's out shopping the "maid" will drop by and the copy the hard drive.
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