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1

http://lmgtfy.com/?q=+On+the+fly+encryption+for+unencrypted+cloud+services%3F ;-) If you use such a service, you lose all of their web based services. So they effectively become purely a storage layer. Not a terrible idea, but removes much of the value from platforms like Dropbox with their countless integrations and so on. There are many such services, ...


1

In my opinion, to password protected zip file is more safe than not to do that. This article explains how to make an encrypted (password protect) compressed file (referred to as 'an archive' file).Note: The compression program built-in to (included with) the Microsoft Windows operating system since the release of Windows XP cannot password protect a ...


1

If you are using a simple passphrase-based approach, then your encryption is at most as secure as your passphrase. And even if you are using a long passphrase, your encryption is at most as secure as the key derivation function used to get from the passphrase to the actual key. Openssl uses a simple MD5 hash to generate the key, which has two drawbacks: It ...


5

I'd recommend simply encrypting the file while it's being uploaded, and before it's written to disk. i.e. encrypt the file while it's being streamed. Assuming you're getting the file in order you can just use standard AES-CBC to encrypt all the blocks of the file and save it to disk. The window of time while the file isn't encrypted isn't terribly ...


2

This is normal. It's how EFS works. Although it is common to refer to file folders with the encryption attribute set as “encrypted,” the folder itself is not encrypted. When encryption is set for a folder, EFS automatically encrypts all new files created in the folder and all files copied or moved into the folder by using My Computer. (Source: ...


2

Assuming AES is being used in any mode other than ECB, the IV is used in the AES encryption (the actual encryption is E_{Ks,IV}(F), not just E_{Ks}(F)). Every mode of operation for AES that I'm aware of except for ECB mode requires an initialization vector, that is used for different things depending on the mode (in CTR it's used to produce the keystream; in ...


2

Generating rainbow tables is never the best way to attack a single instance. Rainbow tables are precomputed tables: you do a lot of computations in advance, under the hope that you will be able to apply these computations to several attack instances. Precomputed tables (rainbow or not rainbow, this does not change anything here) all follow the same pattern: ...


0

I think the only way how you actually can decrypt it now, but not when being tortured is if you either have the chance to destroy/forget the key before you can be made to reveal it. Or the key has a property which makes it unusable in a tortured situation. Many answers address only the part, where you "can not reveal the key to the evil guy, even if you ...


1

EncFS is missing a certain set of safeguards, but it's perfectly safe if you don't use it in such a way that requires protections that it doesn't provide. In particular, EncFS leaks all sorts of metadata: times, sizes, name lengths, filesystem structure, update patterns and more. It also doesn't offer tons of protection if the attacker can control what data ...


-3

I'm going a little sci-fi with this answer. Smart cards, even contactless ones are powerful enough to do cryptography. They often contain a private key, which was generated by them and never leaves the card, but the corresponding public key can be retrieved freely. These smart cards can be protected with a password, they can make themselves inoperable after ...


3

There are very interesting answers there. One warning though: I was once offered to access the ATM of my bank account via a finger scan instead of the typical PIN. I refused. The bank was then assuring me that they guarantee that a copy of my fingerprint cannot be used (yeah, it was a few years ago) I then told them that I am not sure that the bad guys know ...


21

Here is an original technique I have come up with that can survive a rubber-hose attack: Get a stack of cash, about 50 one-dollar bills. Maybe mix some fives and tens in with them. Shuffle them into a random order Derive a password from the serial numbers, for example by taking the two least significant digits from each bill in order to form a 100-digit ...


-6

Here's a plausible scenario Assume that the encrypted file has two passwords (passkeys if you may), one that successfully decrypts the file and one that irreversibly damages the file. For example, it could do a deep format. Let's say that the password which correctly decrypts the file is A and the password which destroys the file is B Extending this, ...


4

While I haven't seen the film, I can easily imagine a randomly generated passcode which changes every [brief time window here]. Some online gaming security protocols started doing this a couple years ago, such as Battle.net (Blizzard - games like World of Warcraft, Starcraft, Diablo) Add in the fact that you can only get the most recent passcode from a ...


4

What you describe here is called a known-plaintext attack. The attacker has at least part of the plaintext, and tries to use it to figure out the key. AES and all other modern encryption algorithms must be able to withstand this type of attack. So the answer is no.


69

Shamir's Secret Sharing is a method for this. It allows one to encrypt a file with a public / private keypair, and then effectively split up the parts of the private key to be distributed to several different people. After that action (and assuming the various parts and original input private key are destroyed after distribution), it would require a quorum ...


46

All of our answers are speculation, of course, but I suspect that the most likely way that the documents are protected are by following Bruce Schneier's advice regarding laptop security through airports: Step One: Before you board your plane, add another key to your whole-disk encryption (it'll probably mean adding another "user") -- and make it ...


-1

It might refer to having multiple possible decryption states. Basically, you start with an extra-large blob of encrypted data, and multiple keys. Each key results in a different document. Obviously, the encrypted data needs to be large enough to hold all documents, but there's no way to prove how many keys exist. Make it large enough to hold 10 documents, ...


6

I haven't seen the documentary, but in addition to what others have spoke about, he could be talking about public/private key encryption. You encrypt a file with the public key provided by an anonymous third party who shares your view. Only they can decrypt the file, and you don't know who they are. So he has a document, encrypt it so it is protected and ...


12

Keyfiles can almost accomplish this. The idea is the encryption key is stored as a file rather than a phrase the user memorizes. Keepass/KeepassX offers keyfiles as an option for securing the password database instead of a passphrase. The key can be more secure because it can be of much longer length than something a human needs to use, but the downside is ...


24

He might be referring to neuroscientific methods of cryptographic primitives such as those outlined in the following paper: https://www.usenix.org/system/files/conference/usenixsecurity12/sec12-final25.pdf Basically, you can prevent against "rubber hose attacks" as they call it (torture the password out of somebody) by training the user via some sort of ...


2

You have to create a hidden volume for two related reasons. If you are arrested by the government and they suspect that some of the data in the encrypted volume is evidence, you can be forced to provide the password. Since TrueCrypt advertises its ability to create a hidden volume and encourages its use (and that's stating it mildly) the government is ...


28

Your first question is really a legal one, and you seem to be assuming two things: The attacker is a government of some sort. That government actually respects citizen privacy and requires some sort of reasonable suspicion before it can force people to give up encryption keys. Neither of those assumptions are necessarily true. For all you know, some ...


4

Your assumptions in 1 are just false in many places. In the US, you cannot be forced to hand over encryption keys. That is not generally the case; in the UK, the Regulation of Investigatory Powers Act makes it a criminal offense to not surrender encryption keys when asked. Assuming "just because they know I encrypt my data doesn't mean they think I'm ...


18

You're wrong in your assumptions. There are many legal jurisdictions where you can be required to produce passwords for encrypted data on suspicion, rather than proof, that the data may be relevant to a criminal investigation. If you don't provide your password, you can be jailed. But if there's no encrypted volume visible, they don't know to do it. For ...


3

Process-based access control only works on data in transient memory (e.g.: RAM). Once data is stored on a semi-permanent media (e.g.: hard drive, flash drive, DVD, etc.), that media can easily be connected to a system that will not honor any access restrictions that are enforced in its native environment. You could add process-based access control to the ...



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