Questions tagged [luks]

LUKS (Linux Unified Key Setup) is a disk-encryption specification.

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89
votes
2answers
83k views

How secure is Ubuntu's default full-disk encryption?

How secure is the encryption offered by ubuntu (using the disk utility)? What algorithm is used underneath it? If someone could at least provide a link to some documentation or article regarding that ...
51
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5answers
13k views

Are there any reasonable TrueCrypt forks?

Unfortunately, TrueCrypt may have been discontinued yesterday. I use LUKS on Linux, but I liked the fact that with TrueCrypt I had a portable solution across Windows, Mac, & Linux. TrueCrypt ...
47
votes
4answers
14k views

Aren't keyfiles defeating the purpose of encryption?

I just added a drive to my system which is basically a partition mounted for extra storage. I'd like to encrypt it to protect my data in case of god knows what, and by doing that I'd need to enter the ...
27
votes
2answers
40k views

Recommended options for LUKS (cryptsetup)

I'm looking for recommended options for cryptsetup to create fully encrypted SSD (SanDisk SSD U100 128GB), which achive: Timing O_DIRECT disk reads: 1476 MB in 3.00 seconds = 491.81 MB/sec Timing ...
27
votes
1answer
47k views

Right way to use the TPM for full disk encryption

I'm currently setting up a BitLocker equivalent using a TPM and LUKS. I've got the basics right and I'm able to measure the boot process and seal the FDE key using the TPM. Every time the sensitive ...
26
votes
3answers
37k views

For LUKS: The most preferable and safest cipher?

I'm about to encrypt two of my hard drives using LUKS, since I can't really do it myself I use the guide on the Arch Linux wiki (which can be found here). In an example in the guide the cipher ...
25
votes
5answers
23k views

What does LUKS header contain?

What is contained inside the LUKS header? I know, the header has size of 2MB. Also, cryptsetup supports "detached header", where the header can be stored in a separate file. Thus, for example, I can ...
20
votes
3answers
6k views

Is LUKS still an effective option for consumer FDE considering Elcomsoft can break it?

I use Fedora Linux and was recently looking into doing Full Disk Encryption on data drives such as /home on some of my / my family's PCs. I understand that LUKS security will be partially dependent on ...
15
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2answers
4k views

Does LUKS protect the filesystem integrity?

I have read in: http://css.csail.mit.edu/6.858/2013/readings/bitlocker.pdf that Bitlocker does not provide data integrity since it takes more space in the disk. The PDF says also that drive ...
12
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3answers
9k views

LUKS, how to make strongest possible and reasonable passphrase?

Let us say I have a volume encrypted under LUKS with a 512-bit key. That would mean there are 2 ^ 512 possible values which the key may be. Now I need a passphrase which is at least as resistant to ...
11
votes
1answer
3k views

Using TPM with well-known SRK/owner passwords?

First, I will explain roughly how I plan to use the TPM: I am using something called tpm-luks which stores a key in both TPM NVRAM and adds the key to one of the LUKS keyslots. The initramfs then ...
9
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3answers
11k views

access to mounted luks partition by non-root user

Recently I searched substitute for truecrypt and played a bit with cryptsetup. The steps I did: mkfs -t ext4 /dev/sdb1 sudo cryptsetup open --type luks /dev/sdb1 enc_vol sudo mount /dev/mapper/...
9
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2answers
4k views

Filling the disk with random data prior to encryption?

Filling the disk with random data prior to encrypting it will supposedly make it harder for the attacker to perform any cryptanalysis. Most sources seem to state this is because it will be harder for ...
9
votes
1answer
652 views

Automatically Open LUKS Container on System Boot in a safe manner

I have a linux system running at a cloud provider where I created an encrypted container using LUKS to store personal data. The encrypted container is manually mounted at /srv; the rest of the ...
7
votes
2answers
4k views

Erasing encryption (LUKS) keys before suspend-to-RAM?

I recently had been wondering if there is a way to erase my LUKS keys from RAM before I suspend my device (usually a laptop) to S3 mode. I am interested in a solution that would work for my / ...
7
votes
2answers
2k views

Is using decrypt_derived more secure than a keyfile?

Say I have two partitions on a Linux system, a root partition (/) and a /home partition. Both of them are encrypted with LUKS. The /home partition needs only to be decrypted if / is unlocked and ...
7
votes
2answers
453 views

Can BTRFS provide authentication on an encrypted disk?

One of the problems of disk encryption is providing authentication. An attacker with access to the ciphertext can modify the ciphertext at will without consequence. Given, this isn't a likely attack, ...
6
votes
2answers
1k views

Luks+Sleep: Login screen security?

Situation: A Desktop Linux (eg. Debian, Xfce desktop, Lightdm login) with LUKS-encrypted partitions (as far as possible, eg. Efi files are not encrypted of course). The computer is in sleep mode (not ...
6
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2answers
2k views

Why does LUKS use CBC?

I read that LUKS uses 256-bit AES with CBC by default. CBC, of course, has the disadvantages that if you change something in the plain text, you have to change everything that comes after it. In the ...
6
votes
1answer
8k views

Use TPM2.0 to securely decrypt the hard drive in Linux -- unattended

I spent several days trying to figure out how to securely decrypt a hard drive on remote location using TPM2.0 in Linux. I'm no security expert and this is my first battle with TPM2.0. I learned a lot,...
6
votes
1answer
3k views

Differences between LUKS and Veracrypt

These two FDE solutions are similar, but I noticed different executions speed: specially mounting a device it seems that Veracrypt takes more time decrypting it. So I would like to compare it with ...
5
votes
2answers
16k views

How to crack encrypted disk (crypto-LUKS) in an efficient way?

I had a disk encrypted by crypto-LUKS but forgotten password. I read a question posted here. LUKS HDD Encryption crack But before that I want to know if there's some free software I can use to ...
5
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1answer
2k views

LUKS TPM disk encryption attacks

Is it possible, or are there any known attacks, to get the encryption key for disk encryption tpm-luks? (Linux LUKS using encryption key stored in TPM) I know that there are attacks like cold boot ...
5
votes
1answer
4k views

Brute Forcing LUKS Full Disk Encryption - Time?

let's say we have encrypted our drive with AES 256 XTS and the following Hash: SHA1 with ~500k Iterations and a 20+ password SHA512 with ~250k Iterations and the same 20+ password. Let's think of ...
5
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2answers
2k views

For remotely unlocking LUKS volumes via SSH, how can I verify integrity before sending passphrase?

Although this is closely related to the recently closed question Evil maids in the server room [closed], I believe that it's more answerable. I'd like to unlock LUKS volumes on remotely hosted ...
5
votes
1answer
192 views

Does mounting a LUKS partition authenticate it?

Can I be sure that the (unencrypted) contents of my LUKS volume were not tampered with if it accepts my passhprase on an otherwise trusted system? In other words, can an attacker with access to my ...
4
votes
2answers
328 views

Does it makes sense to change the LUKS password in every 90 days?

Linux, NetBSD, etc. can be installed with LUKS, so besides the /boot, all other FS will be encrypted. Probably the kernel needs to be booted before the password prompt gets to the user. The LUKS ...
4
votes
2answers
10k views

TrueCrypt VS LUKS Bruteforce Resilience

I have been researching LUKS vs TrueCrypt topics -- my only concern is security, but most of the discussions I see focus around usability / interoperability . I know TrueCrypt has a bunch of nice ...
4
votes
1answer
4k views

LUKS2 dm-integrity

I am using Debian 9.5, Linux Kernel 4.16, I would like to use the dm-integrity feature with cryptsetup. cryptsetup luksFormat --type luks2 <device> --cipher aes-gcm-random --integrity aead ...
4
votes
1answer
2k views

LUKS2 on-disk format specifications

The LUKS1 format has been available for a long time, and the format specifications are easy to find. Recently, LUKS2 has been released, which features a number of important changes, such as AEAD and ...
4
votes
1answer
1k views

Overwriting disk with random data vs. encrypted zeros

Most disk encryption guides recommend to overwrite the disk with random data before encryption, this is discussed here. However the time this takes with the "standard" source of random data can be ...
4
votes
1answer
312 views

Does full disk encryption offer mitigation in the case of the firmware of an SSD being compromised?

Suppose the firmware of an SSD or HDD has been compromised by rogue actors either through "interdiction" (interception) or via the internet. They are able to exfiltrate data and conduct surveillance ...
3
votes
3answers
205 views

Drawback of Multi Level Encryption

I am backing up my files to a RAID mirrored HDD, that has full disk encryption (FDE) in place with LUKS. Until now I did this with rsync, but I recently switched to a new backup program that does file ...
3
votes
3answers
4k views

LUKS nuke efficiency

I am wondering about LUKS nuke patch efficiency. In fact, I think I don't really understand it. From what I know of LUKS, a passphrase is used to encrypt a random key (the master key), which is used ...
3
votes
1answer
1k views

Is it possible to LUKS require both password and key file?

My goal is to be able easily destroy medium with key file in emergency situation and make system unbootable, even is potential advisor knows right password for the system. I'd store this key file in ...
3
votes
1answer
2k views

Change LUKS encryption key (not passphrase) without dataloss

You can change the LUKS passphrase without dataloss, but can you also change the actual key? I reckon you would have to re-encrypt the whole disk, but that would be acceptable to me. Background We ...
3
votes
3answers
8k views

How can I extract the encrypted master key from LUKS header?

I know that a LUKS partition has a plain-text header that stores many informations like master key (MK) digest, MK iterations of PBKDF2, information about the 8 key-slots etc. I also know that in the ...
3
votes
1answer
179 views

Can I secure the bootloader without a TPM?

I have a lot of PCs without a TPM installed. Buying TPMs for all of them is not an option, but I still want to do encryption on them. From what I've studied so far, the entire system/boot partition ...
3
votes
1answer
332 views

How can AES-CBC be used for LUKS encryption, when the ciphertext is not static?

In CBC mode of operation, ciphertext from previous block is used as IV in next block. How then can AES-CBC be used for disk encryption (LUKS), when the data on the disk (ie the ciphertext) keeps ...
3
votes
1answer
396 views

Can government authorities retrieve data from LUKS volume when it's accessed while turned on? [duplicate]

I've heard that there are attacks that can get passwords out of RAM while turned on. If a server, CentOS 7.5 and LUKS enabled, it's tty1 locked, which is on a VMWare hypervisor that is locked with a ...
3
votes
3answers
10k views

Encrypting Tails USB Boot Disk (Live)

To use tails, I have always used a DVD, because of the fact I know it will not be tampered with, at least within reason. However there are endless reasons why a USB boot option would be faster, and in ...
3
votes
4answers
2k views

How safe is dm-crypt/LUKS? Would TPM make me more secure in this case?

I’ve been looking to purchase a new laptop and I need to have security in mind. I’ve specifically been looking for laptops with discrete or integrated TPM because it’s been my understanding that TPM ...
3
votes
3answers
423 views

Should I upgrade old volumes to new cryptsetup encryption mode?

The old cryptsetup default is aes-cbc-essiv:sha256. The new one is aes-xts-plain64:sha256. I don't know that much about cryptography but I assume the standard was changed for a reason. Also there can ...
3
votes
1answer
468 views

Is suspend-to-ram really a meaningful risk for Full Disk Encryption?

Ubuntu offers full disk encryption relying on luks. An often recurring area of criticism is the fact that Ubuntu disables hibernation by default while suspend-to-ram stores the private keys in the ram ...
3
votes
1answer
2k views

Is using trim on a ssd with LVM LUKS safe?

I know that it can allow an attacker to know the filesystem and file size, but can it allow an attacker to decrypt any files?
3
votes
2answers
2k views

Encrypted offsite storage using sshfs and cryptsetup/dm-crypt/LUKS

I'm interested in an encrypted offsite storage scheme, but I don't want to depend on the vendor for encryption. I have an idea for doing so by combining sshfs with cryptsetup/dm-crypt/LUKS, but I'd ...
3
votes
1answer
347 views

Can information somehow be secured from the host on a KVM guest?

With KVM guest systems so prevalent now, I was wondering if there is any merit in using LUKS encrypted storage, as the guest will usually be always on, so the information is always accessible ...
3
votes
1answer
749 views

What’s the security risk when setting the Gnome keyring password to blank on an FED system with autologin?

My system disk is full encrypted with luks. My Ubuntu logs in automatically, because I am the only user. But I still need to unlock my Gnome Keyring and I wonder, if there is any sense for that. ...
3
votes
2answers
999 views

TrueCrypt LUKS keyfile and password

I understand that a TrueCrypt volume may be encrypted with a password AND a keyfile. As far as I can tell, A LUKS volume may use EITHER a password OR a keyfile, but not both simultaneously for ...
3
votes
1answer
403 views

Is scrubbing a ssd drive effective in situations where you can't use the trim command?

I have a luks encrypted external usb ssd drive (Samsung T3) which is unable to use the trim command. This leaves me to search for a different way to securely erase the free space inside the encrypted ...