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What the CIA WikiLeaks Dump Tells Us: Encryption Works

nytimes.com

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Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#131

Post by srssays »

chimeracoder wrote: post #114
acjohnson55 wrote: post #100

Earlier quoted context omitted.

Mathematically unbreakable if your pad is truly random

Sure, but if your RNG is compromised, there's no point talking about encryption in the first place.

That's not really the case. OTP requires a large amount of perfectly unbiased randomness, implicitly from a hardware randomness source (otherwise what you have is more accurately a stream cipher).

Contrast with deriving a key using cryptographic primitives, which can accept low-quality randomness (as long as there is sufficient entropy), that can be easily and transparently collected.

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#132

Post by mikepurvis »

rocqua wrote: post #113
hendzen wrote: post #94

Earlier quoted context omitted.

Agreed. However, the kind of mass surveillance people are worried about isn't really concerned with personal data at rest. That data already requires targeted surveillance to get at. Additionally... unless you generated all the bytes you are encrypting yourself without transmitting them over a network at any time... e.g. video/pictures you took yourself and then stored to your own encrypted disk, your data could be c…

There is still tremendous value in symmetric encryption for off-site storage, especially cloud-based storage. This allows storage to be off-loaded wherever without needing the storage location to be trusted. All that needs to be stored locally is the key. Done right, this means quantum won't get you access to dropbox-like stuff. (Dropbox itself probably doesn't work like that, it'll store the symmetric keys server si…

Dropbox de-duplicates your files with other users who have the same ones, and are capable of serving them all to you through a web site.

There's no encryption there at all, except TLS in transit.

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#133

Post by ekiru »

snakeanus wrote: post #120
MichaelMoser123 wrote: post #107

Earlier quoted context omitted.

Its more of a problem if you have key exchange (like RSA); here [1] it says that with AES is supposedly secure against quantum computers with 'sufficiently sized key sizes'; For key exchange they are trying to adapt elliptic curves. [1] https://en.wikipedia.org/wiki/Post-quantum_cryptography .

Elliptic curves are broken in a quantum setting.

There is an approach (called Supersingular isogeny Diffie-Hellman or SIDH) using certain types of mappings between elliptic curves being researched that _may_ be secure in a quantum setting. (edit to add:) I think this may be what the grandparent poster is referring to by "trying to adapt elliptic curves".

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#134

Post by jacquesm »

snakeanus wrote: post #126
jacquesm wrote: post #122

Earlier quoted context omitted.

A signature is a trap-door, encryption is reversible. So they are two entirely different things, you can't use a signature hash for encryption.

I am not claiming that you can though.

Then you probably meant to start a new thread. The one you are replying to is about encryption exclusively.

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#135

Post by da-bacon »

y7 wrote: post #110
hendzen wrote: post #79

Earlier quoted context omitted.

Symmetric encryption not being broken doesn't really help you if the encryption key has been exchanged using a (presumably quantum-breakable) form of asymmetric encryption. Most encryption in the wild works this way.

True. Note that some "post-quantum" key exchange schemes already exist (based on lattice cryptography, for which there are no known poly-time quantum attacks), e.g. https://eprint.iacr.org/2015/1092 . But I haven't heard of it being used anywhere.

Google has been experimenting with it in chrome https://security.googleblog.com/2016/07/experimenting-with-p... though it is just an experiment in Canary.

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#136

Post by falcolas »

Cyph0n wrote: post #127
hendzen wrote: post #79

Earlier quoted context omitted.

Symmetric encryption not being broken doesn't really help you if the encryption key has been exchanged using a (presumably quantum-breakable) form of asymmetric encryption. Most encryption in the wild works this way.

TLS implements PFS (perfect forward secrecy) by generating an ephemeral asymmetric key pair for the session, usually through DH. In other words, breaking the session key pair will only reveal the plaintext of the current session for the current client. No previous communication is broken, so the NSA would have to traverse the history for each client.

And for a target of interest, given quantum computing, it would not really provide any real protections. I could see how recalculating the key would be well worth it, if you really want the data.

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#137

Post by dredmorbius »

shshhdhs wrote: post #111
praptak wrote: post #80

Earlier quoted context omitted.

One thing you could do is to exchange the keys in a nonstandard way. Phone or whatever. Obviously still breakable but at least not by a standard dragnet.

I wouldn't use the phone for exchanging plaintext keys. You're forgetting about ECHELON, wiretaps, and the dragnets where LEA are ignoring (or purposefully misinterpreting) the law. It's really cheap to store ALL phone calls these days, and just "playback" when you get the legal search warrant.

Exchange many keys.

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#138

Post by dredmorbius »

homakov wrote: post #59
yellowapple wrote: post #54

Earlier quoted context omitted.

It also doesn't have to be a central authority, since "anyone" (meaning: anyone who can afford to operate a mailserver, which is actually a surprisingly-high number) can be such an authority for one's own mail.

Practically nobody is running own mail server these days. Email is extremely centralized

That's true, but not a given.

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#139

Post by smaddox »

mikepurvis wrote: post #132
rocqua wrote: post #113

Earlier quoted context omitted.

There is still tremendous value in symmetric encryption for off-site storage, especially cloud-based storage. This allows storage to be off-loaded wherever without needing the storage location to be trusted. All that needs to be stored locally is the key. Done right, this means quantum won't get you access to dropbox-like stuff. (Dropbox itself probably doesn't work like that, it'll store the symmetric keys server si…

Dropbox de-duplicates your files with other users who have the same ones, and are capable of serving them all to you through a web site. There's no encryption there at all, except TLS in transit.

Found that hard to believe, so I googled it. Not positive this is a trustworthy source, but it sounds like Dropbox does use encryption for files at rest and in motion: https://www.virtru.com/blog/dropbox-encryption/

Re: What the CIA WikiLeaks Dump Tells Us: Encryption Works

#140

Post by xapata »

john61 wrote: post #23
xapata wrote: post #9

Earlier quoted context omitted.

How can you personally verify that any 3rd party service is doing what it claims? Unless you're a security expert with plenty of time to comb through someone else's code, you're still relying on others to be truthful and competent. Even then you're relying on layers upon layers of software and hardware. Far too much for an individual to verify.

You rely on a net of diverse independent reviewers instead of a single entity with a particular interest. A peer reviewed distributed trust net is much more trustworthy.

That single entity consists of many diverse individuals with differing ethics.

As much as the law might try to pretend, companies are not people. Uh, except in the sense that they are compromised of people. So, they literally are people, people combined with capital.

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