109

You can't, plain and simple. If you don't trust the hosting company, you don't host with them. This is law #3 from 10 immutable law of security: Law #3: If a bad guy has unrestricted physical access to your computer, it's not your computer anymore. The hypervisor always have privileged position over your virtualised machine, you can't protect yourself ...


102

In a word: sufficient. This is block-level encryption, so it is filesystem-independent. Ubuntu's transparent encryption is done through dm-crypt using LUKS as the key setup. The built-in default for cryptsetup versions before 1.6.0 is aes-cbc-essiv:sha256 with 256-bit keys. The default for 1.6.0 and after (released 14-Jan-2013) is aes-xts-plain64:sha256 ...


83

The ANSSI, French government service in charge of IT security, has published a document providing brief advice to people having to travel abroad. Relevant here are the advisories concerning preparation before travel: Review the applicable company policy, Review destination country applicable laws, Prefer to use devices dedicated to travel (computers, ...


83

Encryption happens in memory, not on the disk. You are misunderstanding how disk encryption works. It does not read the entire disk and replace it with a decrypted version. Rather, when a file or sector of encrypted data is accessed, it is read into memory and decrypted in memory. Likewise, when writing to the disk, data is encrypted in memory before being ...


73

Two generic things you apparently have missed: In case of disk failure, having the data encrypted at rest solves the issue of having potentially sensitive data on a media you can't access any more. It makes disposing of faulty drives easier and cheaper (and it's one less problem) Full disk encryption also makes it harder for an attacker to retrieve data ...


72

We have two types of encryption here, "file based encryption" and "full disk encryption". There are documented forensics methods and software (e.g. EnCase) that help us detect the schemes and programs used to encrypt the disk. I'm going to take a list of popular tools and standards and see if they leave any traces with which we can determine that they've ...


58

You’re misunderstanding what BitLocker is supposed to protect against. The goal of BitLocker is to protect your data from cold boot attacks (as explained in a Technet blog entry). When you unlock a volume protected by BitLocker, the system gains access to the keys necessary to decrypt the drive and behaves as if it was a regular drive. That is necessary to ...


50

It doesn't decrypt the full disk at startup. Instead, it continously decrypts data as it is read from the disk when it is read from the disk, leaving the actual content on the disk untouched and encrypted. Since decryption is fast in comparison to disk reads, it shouldn't affect the reading speed significantly. Of course, it adds (marginally) to overall load,...


49

Chip-based banking cards typically use a 4-digit PIN. It would take at most a few hours to try them all if the card didn't protect against brute force attempts. The card protects against brute force attempts by bricking itself after 3 consecutive failures. The adversary does not have access to a hash of the PIN (there are physical protections in the card ...


48

At a high level, disk encryption is implemented using a data encryption key (DEK) and a key encryption key (KEK). The DEK is generated randomly and used to encrypt the drive, the KEK is derived from the user's password using a KDF like PBKDF2 or Argon2 and then used to encrypt the DEK. When changing the password, the DEK is simply encrypted with a new KEK ...


43

The advantages are limited, but there are nonetheless scenarios where encryption helps. In any scenario where the attacker obtains the password¹ (with lead pipe cryptography, or far more realistically by reading the unlock pattern on the screen or brute force on the PIN), there is clearly no advantage to full disk encryption. So how could the attacker ...


43

The main obstacle of a TrueCrypt fork is the non-standard TrueCrypt license. While the intention of the authors seemed to be to write a share-alike license similar in spirit to the GPL, the license has a few quite unorthodox passages which can be interpreted in a way which puts unreasonable conditions on a fork. These conditions prevented the Open Source ...


41

I would still choose TrueCrypt for a matter of trust and the "many eyes" theory: After the "TrueCrypt scandal" everyone started looking at the source for backdoors. The TrueCrypt audit finished on April 2, 2015. They found low-risk vulnerabilities, including some that affect the bootloader full-disk-encryption feature, though there is no evidence of ...


40

For the determined attacker setup: The encryption technology used in Android 3 is dm-crypt. The relevant part here is the following: encryption uses a symmetric key, which is derived from the password/PIN typed by the user; the derivation parameters are stored in a LUKS-formatted block on the device itself. Password derivation is salted and uses many ...


38

The short answer is this: We have no idea, probably none. It might protect against stolen backups. But that assumes Amazon even makes backups. That seems very unlikely. If they did, why couldn't they recover data from their last S3 data loss? It's much cheaper and more efficient just to use multiple live copies. Also, Amazon would need the keys on every ...


37

Yes. It could be easily achievable, although it would require kernel support do this properly. In the suspend-to-RAM case, the key should be deleted from the RAM, and in the suspend-to-disk case, from the RAM and also from the disk (or it can be stored encrypted on the disk). A minimal input should be also provided to get the key/reauthentication ...


36

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 random ...


35

How secure is the data in a encrypted NTFS folder on Windows (XP, 7)? What is EFS? Folders on NTFS are encrypted with a specialized subset of NTFS called Encrypting File System(EFS). EFS is a file level encryption within NTFS. The folder is actually a specialized type of file which applies the same key to all files within the folder. NTFS on disk format 3....


33

Yes. Use VeraCrypt. As of September 26th 2015, google's security researchers found a couple of vulnerabilities that affect TrueCrypt 7.1a and VeraCrypt 1.14 they are CVE-2015-7358 and CVE-2015-7359 On September 26th, 2015 VeraCrypt released 1.15 which fixes those vulnerabilities. On October 17th, 2016, VeraCrypt's audit by the QuarksLab has been ...


31

A smart card works by keeping a secret hidden and answering a challenge that proves it has the secret. It, theoretically, should never reveal that secret to anyone and it should be unrecoverable. There are some technical ways you might be able to get around it, but most of them are destructive to the card. This means you know if your smartcard has been ...


28

One benefit of full-disk encryption is that it makes wiping the flash storage very fast. All of the data stored on the device is stored encrypted under a particular encryption key K. The system also stores an encryption of K under the user's PIN. To wipe the entire drive, all you have to do is wipe the spot that stores the encryption of K (which is just ...


28

I would still recommend using secure delete in your scenario. Should your machine be compromised when you are logged in (malware etc), full disk encryption will not protect you from a undelete operation via C&C malware for example. SSDs have problems erasing files but a number of manufacturers provide utilities for their drives to securely erase a file ...


25

Before you read all this, remember that this technique is at least 5 years old -- it's probably much easier by now (see the other answers). (But it sure was fun to figure this all out.) I did this a few years ago with Fedora 10 and Windows Vista to demonstrate how all the intricacies fit together. It was a bit involved (mostly because Windows Vista doesn't ...


22

There are a number of defenses you can use to help prevent and recover from theft. The first thing you should look into is full-disk encryption, e.g. LUKS, TrueCrypt, or PGP. This will prevent an attacker from reading any data on the disk, even if they steal the hardware. You will need to enter the password at boot, though, so for unattended remote hardware ...


21

LVM operates below the filesystem, so whatever it does, it does so at the disk level. So yes, indeed, when LVM implements encryption this is "full-disk encryption" (or, more accurately, "full-partition encryption"). Applying encryption is fast when it is done upon creation: since the initial contents of the partition are ignored, they are not encrypted; ...


21

It's (theoretically) harder to duplicate a Smart Card. You can duplicate a USB drive easily. If I steal both, you are equally in trouble, but if I steal the USB, duplicate it, then replace it without you knowing, then you are in trouble and you don't know it.


20

If the decryption key is stored in plain on the very same media as the encrypted data, then the encryption is pointless. If you have a set of rules, which require data to be encrypted, but permit storing the key in plain on the very same media, then the rules are flawed. If you ever face such a flawed set of rules, you should point out the flaw. If the key ...


20

Can anyone point out any weakness in this setup, and if you do, how to make it secure? Hardware solutions exist which can grab your system's memory without needing your login. And that's pretty much the weakness - if someone can get access to your system's memory, those passwords (or, at worst, the keys formerly unlocked by those passwords and still in ...


19

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 ...


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