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If you're in a country where the government would torture you indefinitely just for suspecting that you have a hidden TrueCrypt volume, you're probably screwed

If you're in a country where the government would torture you indefinitely just for suspecting that you have a hidden TrueCrypt volume, you're probably screwed anyway if you ever appear on their radar. At that point you probably did something else besides using encryption that would be sufficiently susicious to get you tortured. Plausible deniability is simply not a useful defense against someone that would decide to torture you for a mere suspicion.

leephillips 13y ago
Right, the analysis in the article assumes that there is no cost to the government of indefinite torture. Is it possible to hide the fact that you have a Truecrypt volume? Or are there always headers or signatures that give it away?
- izzydata 13y ago
  I thought full disk encryption left the drive looking entirely unformated. Although you'd probably have truecrypt installed on the computer. You would also want to not save volume mounting history. But if you had truecrypt installed and 1 drive that wasn't formatted... Yea
- pja 13y ago
  A large chunk of unexplained high entropy data is a bit of a giveaway. You can't really hide the fact that you're using encryption, because it doesn't really look like anything else apart from random data & people don't usually go around piping /dev/random into large files for no good reason. Compressed data is high entropy, but can be decompressed to something lower entropy, so you can easily eliminate png filess, zipped files etc.
  - deleted 13y ago
    [deleted]
betterunix 13y ago
It is not just about torture. You might be penalized by a judge for failing to disclose your "other password" regardless of whether or not it actually exists -- you might even be asked to prove that there is no other password. A customs officer might refuse to allow you to bring your laptop across the border until you enter your "other password," also regardless of whether or not there actually is another password. It is also worth pointing out that the number of passwords you deny having is completely irrelevant. You could claim to have forgotten the one password you use for non-deniable encryption and the effect would be the same (and your story is equally plausible). It is much easier to claim to have forgotten one password than to try to maintain an innocent partition, so you might as well just do that.
- dnbl 13y ago
  >You might be penalized by a judge for failing to disclose your "other password" regardless of whether or not it actually exists Judges can penalize only if the existence of password is beyond reasonable doubt (if it is "free world" we are talking about). Give me one real world example of a person getting penalized for hiding the "other second password". >A customs officer might refuse to allow you to bring your laptop across the border until you enter your "other password" Again, please give me one real world example for that. I don't think it has ever happened, yet. Enter the decoy password and customs officer is happy. >It is much easier to claim to have forgotten one password than to try to maintain an innocent partition, so you might as well just do that. People DO get jailed for that. "I forget the password" doesn't help if you have an encrypted partition because it is beyond reasonable doubt that you have a password. This is why deniable encryption works in field, it is opportunistic. You can give away the decoy password and get rid of the suspicion. Until there is a real world example against it, I am convinced that it works. Situation today: Non-deniable encryption: Torture happy country: You are screwed anyway. With or without giving your password. Non torture country: You get penalized for non disclosure. Deniable encryption: Torture happy country: You are screwed anyway. With or without giving your password. Non torture country: There is a good chance that you can get away by giving the decoy password. Deniable encryption is not a silver bullet, your OS can leak the existence of it in logs if you are not using FDE, usage errors, malware etc can mess it up. Torture or judge claiming the other password out of blue is NOT an argument against it though, because you are screwed with or without giving all the passwords if it ever happens.
chiph 13y ago
"We think you have another partition, and we're going to lock you up until you admit it and supply the password." - Tomás de Torquemada, 2011
- Xymak1y 13y ago
  Relevant xkcd: http://xkcd.com/538/ http://xkcd.com/538/
midas007 13y ago
Yup. Plausible deniability only works if a strategy is unlikely to be known by an adversary. In this case, it is widely known that TrueCrypt has hidden volume capabilities, so there's not much of a veil of ignorance to hide behind. Btw: there's no explicit restriction on N-level deep of hidden volumes, but TC won't automatically make the outer ones read-only.

leephillips 13y ago

Right, the analysis in the article assumes that there is no cost to the government of indefinite torture. Is it possible to hide the fact that you have a Truecrypt volume? Or are there always headers or signatures that give it away?

izzydata 13y ago
I thought full disk encryption left the drive looking entirely unformated. Although you'd probably have truecrypt installed on the computer. You would also want to not save volume mounting history. But if you had truecrypt installed and 1 drive that wasn't formatted... Yea
pja 13y ago
A large chunk of unexplained high entropy data is a bit of a giveaway. You can't really hide the fact that you're using encryption, because it doesn't really look like anything else apart from random data & people don't usually go around piping /dev/random into large files for no good reason. Compressed data is high entropy, but can be decompressed to something lower entropy, so you can easily eliminate png filess, zipped files etc.
- deleted 13y ago
  [deleted]

betterunix 13y ago

It is not just about torture. You might be penalized by a judge for failing to disclose your "other password" regardless of whether or not it actually exists -- you might even be asked to prove that there is no other password. A customs officer might refuse to allow you to bring your laptop across the border until you enter your "other password," also regardless of whether or not there actually is another password. It is also worth pointing out that the number of passwords you deny having is completely irrelevant. You could claim to have forgotten the one password you use for non-deniable encryption and the effect would be the same (and your story is equally plausible). It is much easier to claim to have forgotten one password than to try to maintain an innocent partition, so you might as well just do that.

dnbl 13y ago
>You might be penalized by a judge for failing to disclose your "other password" regardless of whether or not it actually exists Judges can penalize only if the existence of password is beyond reasonable doubt (if it is "free world" we are talking about). Give me one real world example of a person getting penalized for hiding the "other second password". >A customs officer might refuse to allow you to bring your laptop across the border until you enter your "other password" Again, please give me one real world example for that. I don't think it has ever happened, yet. Enter the decoy password and customs officer is happy. >It is much easier to claim to have forgotten one password than to try to maintain an innocent partition, so you might as well just do that. People DO get jailed for that. "I forget the password" doesn't help if you have an encrypted partition because it is beyond reasonable doubt that you have a password. This is why deniable encryption works in field, it is opportunistic. You can give away the decoy password and get rid of the suspicion. Until there is a real world example against it, I am convinced that it works. Situation today: Non-deniable encryption: Torture happy country: You are screwed anyway. With or without giving your password. Non torture country: You get penalized for non disclosure. Deniable encryption: Torture happy country: You are screwed anyway. With or without giving your password. Non torture country: There is a good chance that you can get away by giving the decoy password. Deniable encryption is not a silver bullet, your OS can leak the existence of it in logs if you are not using FDE, usage errors, malware etc can mess it up. Torture or judge claiming the other password out of blue is NOT an argument against it though, because you are screwed with or without giving all the passwords if it ever happens.

chiph 13y ago

"We think you have another partition, and we're going to lock you up until you admit it and supply the password." - Tomás de Torquemada, 2011

Xymak1y 13y ago
Relevant xkcd: http://xkcd.com/538/ http://xkcd.com/538/

midas007 13y ago

Yup. Plausible deniability only works if a strategy is unlikely to be known by an adversary. In this case, it is widely known that TrueCrypt has hidden volume capabilities, so there's not much of a veil of ignorance to hide behind. Btw: there's no explicit restriction on N-level deep of hidden volumes, but TC won't automatically make the outer ones read-only.