74
votes
Accepted
Aren't keyfiles defeating the purpose of encryption?
If decryption only relies on the keyfile and this keyfile is readily available, there is indeed no significant security benefit in your setup.
What you can do though is store the keyfile on a ...
- 7,419
57
votes
Accepted
Is LUKS still an effective option for consumer FDE considering Elcomsoft can break it?
No, Elcomsoft cannot break LUKS or Veracrypt. What they do is to guess the password. Any password-based encryption mechanism can be broken by guessing the password: this is not a flaw in the ...
21
votes
Is LUKS still an effective option for consumer FDE considering Elcomsoft can break it?
While LUKS offers strong protection against brute force attacks by using thousands of iterations of a hash function during key derivation, we have significant advances in password recovery attacks ...
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17
votes
What does LUKS header contain?
I believe that the header results being 2MB large because of the Anti-Forensic splitter: the encrypted master key is splitted in several blocks to enhance the diffusion and make sure that it can be ...
- 401
15
votes
Does LUKS protect the filesystem integrity?
LUKS formatted with --integrity <algorithm> option will provide integrity protection for the encrypted volume.
For that to work, --type luks2 must be used when formatting the device (opening of ...
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14
votes
What does LUKS header contain?
For your information, I can't answer "Authoritatively" because I am not the author/contributor of LUKS/cryptsetup/dmcrypt but a user. But my answers are following,
What does LUKS header ...
- 1,146
12
votes
Aren't keyfiles defeating the purpose of encryption?
While Demento's answer is fine, I'd also present another user case I'm personally using: I have full disk encryption set up — using LUKS on a Linux-based box, and the scheme is implemented as follows:
...
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10
votes
For LUKS: The most preferable and safest cipher?
Most preferable cipher is aes-xts-plain64 and it is used distro wide (RedHat, CentOS, Oracle Linux, Ubuntu) by default. Most of the people use AES because lots of the appliance, application support ...
- 1,146
9
votes
What does LUKS header contain?
As taken from https://www.lisenet.com/2013/luks-add-keys-backup-and-restore-volume-header/, you can see that the cryptsetup luksDump command will explain the contents. One header should be able to be ...
- 38.3k
8
votes
access to mounted luks partition by non-root user
TLDR: Mount the filesystem in the user's home directory.
This is not specific to luks since it applies to mounting in general. I have not tested with ext4 but I don't see a reason why it will be ...
- 166
8
votes
LUKS2 dm-integrity
The dm-integrity authenticated encryption support for block devices is part of the Linux kernel since version 4.12.
If it's enabled in your kernel then it should be automatically loaded, when needed.
...
- 550
7
votes
What does LUKS header contain?
I believe I have found the answer to your question. The header is made up of the header itself and a space for keyslots. The reason for this section behind the header to be 2MB is by default. Here is ...
- 1,049
7
votes
access to mounted luks partition by non-root user
For future readers:
Freshly formatted filesystem's root has usually rights of rwxr-xr-x and indeed is writable by root only.
On the first mount, depending on the future use of this partition - ...
7
votes
Accepted
How to crack encrypted disk (crypto-LUKS) in an efficient way?
It depends what kind of encryption/format you have. Currently, there are many formats which cryptsetup support. Basically, the most popular are LUKS1 and LUKS2. You can check what kind of format you ...
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6
votes
Accepted
LUKS2 on-disk format specifications
Update: A full specification PDF for version 1.0.0 of the LUKS2 on-disk format can now be found in docs/on-disk-format-luks2.pdf. (It's a permalink, so check the master for updated versions.)
It's in ...
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6
votes
Is it possible to LUKS require both password and key file?
LUKS does not support requiring both a keyfile and a passphrase to decrypt. The encrypted volume can be decrypted as long as you provide satisfactory credentials to any one of the configured keyslots. ...
- 66.5k
5
votes
Accepted
LUKS TPM disk encryption attacks
The TPM is used to seal the LUKS secret and nothing else. Once decrypted by the TPM (i.e. the proper environment has been loaded) the secret is stored in RAM hence it can be captured by coldboot ...
- 1,423
5
votes
Is LUKS effective?
If you don't select overwrite empty disk space option with LUKS, it is quick and not quite as secure. You are comparing LUKS's quick, less secure usage with Bitlocker's secure usage.
If you selected ...
- 469
5
votes
Luks+Sleep: Login screen security?
Assuming all relevant SysRq features are disabled when the lock screen is active (SAK, sending SIGTERM or SIGKILL to all processes, triggering the OOM killer as you mentioned, etc), and assuming ...
- 66.5k
5
votes
Accepted
Does full disk encryption offer mitigation in the case of the firmware of an SSD being compromised?
Partially. Full disk encryption, when done through software (e.g. LUKS), means that a compromised storage device will only ever see encrypted data, never decrypted data. It will never have access to ...
- 66.5k
5
votes
Accepted
How difficult is it to decrypt a disk encrypted with luksOpen?
I'm wondering how difficult is it to decrypt this disk using bruteforce password guessing?
It's not difficult, but it's time consuming. You only need the LUKS header and a lot of processing power. ...
- 53.5k
4
votes
How can I extract the encrypted master key from LUKS header?
It looks like this is what you want. It creates a copy of the header, without making any assumptions about the header size.
# cryptsetup luksHeaderBackup /dev/sda5 --header-backup-file /tmp/luks-...
- 66.5k
4
votes
Accepted
Laptops SSD: Hardware Encryption plus DM-Crypt/Luks - Security and Performance
Using only hardware encryption means you have to trust the SSD in addition to trusting the OS and CPU/RAM. With LUKS, you only need to trust the OS and CPU/RAM.
In practice, either one should do the ...
- 31.4k
4
votes
Accepted
How can AES-CBC be used for LUKS encryption, when the ciphertext is not static?
This is actually a quite tricky problem with no perfect solution.
If the file system was one were data is written only once and written entirely sequential, a single CBC encryption all the way from ...
- 5,482
4
votes
Accepted
Limit of 256 bit drive encryption? 512 needed for large drives?
AES is a block cipher. Wikipedia says:
The winner of the AES contest, Rijndael, supports block and key sizes of 128, 192, and 256 bits, but in AES the block size is always 128 bits. The extra block ...
- 9,253
4
votes
Should I upgrade old volumes to new cryptsetup encryption mode?
There is no security advantage to AES-XTS over AES-CBC-ESSIV—in fact, in the standard threat model for disk encryption (an adversary can read multiple snapshots of a disk, e.g. because of bad sectors ...
- 2,656
4
votes
LVM on LUKS implementation
Unfortunately you are mistaken on several key points.
LVM on LUKS is the only secure option for encrypting a Linux/Ubuntu USB system.
There are other options, such as VeraCrypt, or using dm-crypt ...
- 15.6k
4
votes
Accepted
What is a LUKS cipher-name "@"?
The cipher-name in your example is not '@'. The field you're looking at is actually the hdr_size field.
The mistake you've made is trying to decode a LUKS2 container with LUKS1 encoding. In the table ...
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