UK asked N.Y. Times to destroy Snowden material | Hacker News Reader

UK asked N.Y. Times to destroy Snowden material

reuters.com

42 pointsprimroot28 comments

It's all very confusing so no point rushing to any conclusions.

The Register writes:

"the government says that Miranda was actually carrying a piece of paper with a decryption password written on it. This allowed the police to read at least some of the files he was carrying." [1]

While Greenwald just tweeted:

"Anyone claiming that David Miranda was carrying a password that allowed access to documents is lying. UK itself says they can't access them."[2]

[1] http://www.theregister.co.uk/2013/08/30/snowden_journos_boyf...

[2] https://twitter.com/ggreenwald/status/373451644794449922

It's very possible that both statements are true.

1) We know that the UK can imprison people who refuse to disclose encryption keys.

http://en.wikipedia.org/wiki/Key_disclosure_law#United_Kingd...

2) Miranda could have been carrying a valid password written on a piece of paper so he would not be jailed simply for failing to remember a complex password.

3) That password might decrypt one or more TrueCrypt containers, with 20GB of unimportant decoy documents.

4) In addition to the 20GB of decoy documents, the TrueCrypt containers could contain hidden volumes for plausible deniability, encrypted with different keys that Miranda did not know.

http://www.truecrypt.org/docs/hidden-volume

http://www.truecrypt.org/docs/plausible-deniability

5) If the UK authorities didn't discover the hidden volumes until after Miranda had been released, they're left with a bunch of decoys and 40GB they can't decrypt.

That makes no sense. If you can decrypt 20 gigabytes of a TC volume you can access the other 40 too.

There are few explanations

1. The 20 gigabytes in question were not encrypted (which coincidentally is the size of a windows installation)

2. The 75 files were temp files

3. They managed to open 60 gig container but could not access the hidden volume

The third option makes sense with the decryping passphrase being in possession of Miranda - the first 20 GB are a warning.

Possibly there are two TrueCrypt volumes, one of which was accessed and one of which was not (yet).

Or... can you encrypt another volume inside of a TrueCrypt-encrypted volume?

Yes you can - but you need the outer volume to have fat style file system where the OS won't write randomly (not sure which of the *nix ones is suitable for that) at the higher addresses. You basically say - from this address on is a hidden volume and there is new volume header with new master key that needs to be mounted separately.

Reading the report at its face, it doesn't say the encrypted data was obtained.

It says:

1. Goode said the hard drive contained around 60 gigabytes of data

2. "of which only 20 have been accessed to date."

3. She said that she had been advised that the hard drive contains "approximately 58,000 UK documents which are highly classified in nature, to the highest level."

4. Goode said the process to decode the material was complex and that "so far only 75 documents have been reconstructed since the property was initially received."

Let's assume (as a possibility) that:

1. It's a 60GB hard drive 2. It has a 40GB Truecrypt partition 3. There are deleted files on the 20GB partition that were not securely erased

This theory does not explain everything, but might it be plausible?

Yes, absolutely.

  Goode said "renders the material extremely difficult to access."

That's government-speak for "resort to brute force." The ability to break RSA would do the government more damage than it would do Miranda. If they have broken RSA they aren't admitting it.

Perhaps Miranda needed to transfer some of his sensitive data to a machine he couldn't supply the password to. (Maybe he thought the machine might be unsafe or keylogged etc.) Or maybe the 20 GB partition was his "plausible deniability" partition and he surrendered that key to avoid getting arrested.

After moving the files to his unencrypted partition, he could access them on any machine by simply plugging in the hard drive. He should have securely erased the data after he was done, yes, but that can be difficult when traveling.

This can be seen as an interesting commentary on the legitimate usability problems with using crypto, even though the crypto itself is doing its job just fine.

TrueCrypt doesn't use RSA or any asymmetric cryptography.

"In her witness statement submitted to the British court on Friday, Detective Superintendent Caroline Goode, who said she was in charge of Scotland Yard's Snowden-related investigation, said that among materials officials had seized from Miranda while detaining him was an "external hard drive" containing data encrypted by a system called "True Crypt," which Goode said "renders the material extremely difficult to access."

Goode said the hard drive contained around 60 gigabytes of data, "of which only 20 have been accessed to date." She said that she had been advised that the hard drive contains "approximately 58,000 UK documents which are highly classified in nature, to the highest level."

Isn't this supposed to be very unlikely to happen when using TrueCrypt? Can someone explain what could have gone wrong in the process of storing this data?

It would appear that governments are able to somewhat efficiently bruteforce TrueCrypt volumes and access a little bit of data at a time. I couldn't get anyone interested in this article, but I would also like to know what's going on here. If a TrueCrypt volume can be broken for a small-time case of a child porn possession, that would seem to have dramatic ramifications for the security of pretty much everything in the world.

Unless RSA is still solid and it's just TrueCrypt.

Can any crypto experts comment?

They said on the news that he had the password written down on a piece of paper (which was also seized / found during the search). I don't think there's any mystery here.

That sounds like a line they'd use to try and cover up the abilities of GCHQ (or whoever) to access such filesystems. If they had the password then what prevented them from accessing the whole volume?

If they found the password, they would have all the drive. Not just part of it. Right?

That article provides no suggestion whatsoever that the government is able to efficiently bruteforce truecrypt. I think everyone can agree that if any part of the government had better-than-brute force capabilities for truecrypt, the FBI would absolutely not be allowed to disclose or make use of that capability in a child porn case.

More likely explanations: Forensics recovered the password from an unencrypted volume, or he had a really dumb password, and he probably reused it somewhere.

RSA is asymmetrical algorithm. They rely on mathematical problems being hard.

TrueCrypt use symmetrical - AES Twofish and Serpent and you can even cascade them. RSA and AES have nothing in common. So a mathematical breakthrough in RSA will not help at all with making AES insecure.

The problem with assessing the statement is that it went through multiple people who don't have first hand knowledge of the actual incident, and who don't have a technical understanding of what they are even talking about. Details are subtle but they matter.

Apparently he had the password written down, and there were instructions and a key on the disk, according to various stories. Seems like Snowden gave them the key or something it seems odd.

If one believes the report of the NY Times, I'd doubt that hewould have left traces of files left on the computer they took with them, the article explicitly mentions Poitras (who Miranda alegedly had met in Berlin) wiping harddrives completely before crossing borders:

http://www.nytimes.com/2013/08/18/magazine/laura-poitras-sno...

Also, with TrueCrypt (or any other well-designed full disk encryption software) I'd not expect single files to be discovered, it should be either all or nothing.

I don't know much about RSA/TrueCrypt... but surely a file ordered: A+B+C+D+E+F+G wouldn't be stored as enc(A)+enc(B)+enc(C)+enc(D)+enc(E)+enc(F)+enc(G). If they are able to access 20GB of the volume, what would stop them from accessing the other 40GB?

Truecrypt allows "hidden volumes" to reside inside the same encrypted volume. So maybe they had one password which allowed access to the first 20 GB, but the rest is still encrypted?

A big thank-you to the HN mods for not rewriting this posts headline to match the article's. Although "UK asked N.Y. Times to destroy Snowden material" matches the main focus of the article, the part involve TrueCrypt is what makes it applicable to the HN audience.

So a big round of applause for not clobbering this article's rewritten headline - you're all called out far too often for doing negative work and deserve acknowledgement for doing good;-)

Snowden must have really hit the jackpot.

It will be interesting to see what else comes out.

I'm disappointed in how Greenwald planned the whole thing. Did he really not expect this to happen - especially in UK? Why didn't he have Miranda delete the files as soon as he gave them to Laura Poitras or whatever he did with them in Germany.

Now, whatever Greenwald wants to release next needs to be done fast, before the governments prepare well crafted rebuttals to whatever he's releasing, because they'll know what he'll release next.

What I don't understand is why anyone would bother physically transporting such files at all. Why not just encrypt them, upload them to a server and have Poitras download them?

Put them on a tor hidden server if there is concern about someone finding the box directly, and bring the box down once the download is complete.

I have asked myself this too. Also since Laura is good at using crypto according to the media I would have expected for them to have created a few key pairs while together in the US and a few terabytes worth of one time pads. So they can just encrypt the volume headers with them.

What I don't understand is why anyone would bother physically transporting such files at all.

Even if they had a reason to physically transport then, what I don't understand is why he flew through London since there are several daily non-stop flights between Frankfurt and Rio.

Is it possible they just wanted even more news exposure?

Don't give up yet. Reading about TrueCrypt's other features (hidden volumes, plausible deniability) makes me think this might still be a deep troll by Greenwald. We'll see!

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