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

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Change password on a LUKS filesystem without knowing the password

I have a Debian Wheezy server that's been running for a while with an encrypted drive. The password for the encrypted drive (/dev/sda5) was lost when my encrypted password file was corrupted. I'd ...
11
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3answers
2k views

How to open a port early in boot process to unlock LUKS via SSH

I have a fully encrypted server running Debian 7 and have set up dropbear and busybox to unlock the LUKS container via SSH (as described in this tutorial and in this U&L answer). Unfortunately, ...
9
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2answers
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How to mount a cryptsetup container just with `mount`?

I created an encrypted container via #!/bin/bash dd if=/dev/zero of=$1 bs=1 count=0 seek=$2 MAPPER=$(mktemp -up /dev/mapper) LOOPDEV=$(losetup --find --show $1) cryptsetup luksFormat $LOOPDEV ...
9
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1answer
263 views

Defending against the evil maid, how to handle removal of the /boot partition

When using LUKS full disk encryption, how would you go about protecting against evil maids ? The evil maid attack is when someone gets physical access to your computer while you're away and ...
8
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1answer
4k views

Linux: LUKS and multiple hard drives

I have a Debian Linux system (amd64) installed on a RAID-1 system encrypted device (LVM on LUKS) and will have a RAID-6 of >=4 disks where I'll put my data (LUKS and maybe LVM). I think the basic ...
7
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2answers
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How to change the hash-spec and iter-time of an existing dm-crypt LUKS device?

How can I change the hash-spec and iter-time of an existing dm-crypt LUKS device? Clearly I can pass the options if I create a new device, for example something like this: sudo cryptsetup ...
7
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1answer
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Can Grub2 multi-boot LUKS/LVM distros with only one boot partition?

There are many tutorials on the internet for multi-booting unencrypted distros using a single boot partition and chainloading. For example, booting 145 OSes. Likewise, there are tutorials for ...
6
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Which partitions should I encrypt?

My laptop is currently running Windows and Fedora, but I'm planning to install Arch Linux as my sole OS soon. This current setup is using whole disk encryption through TrueCrypt, but I'm unsure if it ...
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4answers
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How to identify LVM-over-LUKS or LUKS-over-LVM

I recently installed Fedora 20. I don't recall what exact options I chose for encrypting the disk/LVM during installation. It installed fine and I can log in etc. Here is the situation I have: I ...
6
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1answer
234 views

Cannot run cryptsetup throught SSH?

I'm trying to open a LUKS drive through SSH directly. ssh root@XX "cryptsetup luksOpen /dev/sdb3 secure But, no password prompt and it stuck. debug1: Sending command: cryptsetup luksOpen /dev/sdb3 ...
6
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1answer
979 views

List open dm-crypt LUKS volumes

If I mount a simple loop device, losetup -a give me the devices opened. Is something similar possible with cryptsetup?
6
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1answer
4k views

Grub-install: embedding is not possible in Bios/GPT

I am struggling with setting up an encrypted NAS for some days now. The basic plan is to have btrfs on lvm on luks on raid1 with lvmcache in writeback mode thrown in for the root partition to reduce ...
6
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1answer
156 views

LUKS key from known password?

I have a hard drive with Ubuntu 14.04 installation - root partition was encrypted with LUKS. I had some configuration problems and wanted to re-install Ubuntu but keep all my data so I moved all my ...
6
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1answer
1k views

Trying to understand LUKS encryption

I decided to encrypt my root partition with LUKS+LVM. My ThinkPad setup: Samsung 830 128GB SSD 750GB HDD Core 2 Duo 2,5 GHz P9500 8GB RAM But the more I read, the less I understand about those ...
6
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1answer
859 views

How to have Linux wipe/randomize/sanitize RAM at shutdown?

For mysterious reasons I still double boot sometimes into Windows. My problem is that I fear that information may leak because the RAM memory is accessible to Windows. (the Linux partitions are ...
6
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2answers
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How to choose LUKS encryption when installing RHEL 6?

With the default RHEL 6 installer, how can I choose the LUKS encryption? Afaik if I prepare the disk like cryptsetup luksFormat -c cast5-cbc-plain -s 128 /dev/$DEVICE could be the "fastest" ...
6
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1answer
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Umount all attached usb disks with a single command

Is there a (safe) way to umount all partitions on all attached usb devices (usb-hdds, usb-sticks) with a single commandline command, including several encrypted luks partitions? Only the partitions ...
5
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1answer
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How to remove LUKS encryption?

I tried removing LUKS encryption on my home directory using the following command: cryptsetup luksRemoveKey /dev/mapper/luks-3fd5-235-26-2625-2456f-4353fgdgd But it gives me an error saying: ...
5
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2answers
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RHEL6 LUKS with TPM support?

I'm surprised that this question is not asked more frequently, but (in RHEL) does LUKS support TPM's the way that Windows BitLocker does? If so, how is this feature implemented, and does it provide ...
5
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3answers
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Poor IO due to LUKS/Software RAID/LVM ordering?

I'm trying to determine if I should re-setup my RAID array due to poor IO performance. First off, the system: i7 920 4 4TB WD 5400 Green drives CentOS 6.3 host Secondly, the disk setup: ...
5
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3answers
3k views

Best practice to backup a LUKS encrypted device

What's the fastest method to backup and restore a luks encrypted device (e.g. a full encrypted usb-device to a image-file). The usb-device can be decrypted/accessed. I'm looking for a solution to ...
5
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2answers
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How can I shrink a LUKS partition, what does `cryptsetup resize` do?

I am in progress of resizing a LUKS encrypted partition that contains a single ext4 filesystem (no LVM or something). The cryptsetup FAQ recommends to remove the old partition and recreate it, but ...
5
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1answer
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LUKS storing keyfile in encrypted usb drive

I already asked once about LUKS unlocking of multiple HDDs in Linux: LUKS and multiple hard drives. Now I would like to know how to secure store the keyfile used for the automatic unlock of the ...
5
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1answer
124 views

Why are logical volumes used with LUKS partitions?

All of the instructions I've seen on setting up a LUKS encrypted drive require using logical volumes to create root and swap partitions inside a LUKS device. Why not just put standard partitions ...
5
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1answer
71 views

Is there an unencrypted but signed filesystems?

I'm curious if there is a filesystem that's unencrypted, making it readable by anyone, but employs a digital signature scheme so as to require that writes be digitally signed. I suspect the answer ...
5
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1answer
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Abysmal general dm-crypt (LUKS) write performance

I am investigating a problem where encrypting a block device imposes a huge performance penalty when writing to it. Hours of Internet reading and experiments did not provide me with a proper ...
5
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3answers
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LVM Ontop of LUKS using Grub

What am I trying to do? Install Arch with full system encryption (sans boot and media partition) using LVM on top of LUKS on an external hard drive (sdb) using: ...
5
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1answer
752 views

How to decrypt an encrypted container via ssh without entering a passphrase while requiring some client authentication?

I log in to a server via public key authentication and then mount a container (using e.g. LUKS/dm-crypt or truecrypt). At the moment, I have to enter the container password manually. Is there a way to ...
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4answers
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Can I use scrypt to hash for LUKS?

Can scrypt be used as the hashing algorithm for LUKS? Can I tune its parameters? How can I do this?
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2answers
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Why does LUKS need to generate hash values?

If you create a new LUKS device, you can specify the option -hash and -iter-time. For example like this: sudo cryptsetup luksFormat --cipher aes-cbc-essiv:sha256 --key-size 256 --iter-time 2100 ...
4
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3answers
485 views

Can I overwrite LUKS partition with it's decrypted content?

I have HDD with my data (partial backup of most important data available on other HDD), currently it's formatted as Ext4 over LVM over LUKS. I want to remove LUKS layer, but reformatting and data ...
4
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2answers
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Are there more advanced LUKS key schemes, e.g. 2 of 3 keys needed?

It seems like the two main LUKS encryption options are: USB keyfile (see http://superuser.com/questions/149578/how-can-i-use-a-keyfile-on-a-removable-usb-drive-for-my-encrypted-root-in-debian) ...
4
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2answers
321 views

LUKS encryption for tape media?

I was wondering, if it was possible to use LUKS encryption with tape drives, QIC for instance. I'm using LUKS for USB drives and internal disks, even DVDs and CDROMs. But I was thinking of maybe ...
4
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1answer
71 views

What is the proper way to unlock a root filesystem spanning two LUKS devices by only entering the password once, using systemd?

I have been having a lot of issues getting an encrypted multi-disk root filesystem to boot up reliably under systemd on Debian Jessie while only having to enter the password once. Previously I've ...
4
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1answer
227 views

Meaning of fsync() in sshfs+LUKS setup

Background: I'm investigating methods for encrypted storage on untrusted machines. My current setup uses sshfs to access a LUKS-encrypted image on the remote machine, which is decrypted locally and ...
4
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1answer
283 views

File containing ext filesystem

Let's suppose I create a file, map it to /dev/loop0, and create a LUKS partition inside dd if=/dev/zero of=myfile bs=1M count=1000 losetup /dev/loop0 myfile cryptsetup -c aes-cbc-essiv:sha256 -s 256 ...
4
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1answer
977 views

BCache and disk encryption

I recently bought a new laptop with a 16Gb mSATA SSD cache drive. I haven't used that one yet. I have, however, opted for Ubuntu 13.04 with "Full Disk Encryption" for the main partition (is that ...
4
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1answer
117 views

Encrypted filesystems with swap partitions

A common error that happens with Ubuntu, though not Ubuntu in particular is the options of being able to encrypt the file system at installation time which creates an encrypted swap partition with ...
4
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1answer
164 views

Dropbear terminates before LUKS password prompt on Debian Jessie

I'm trying to use dropbear as a ssh server to unlock an encrypted partition which was created during Debian 8.2 setup. It boots to the password prompt (and unlocks if correct password is typed) but ...
4
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3answers
2k views

Unlock LUKS encrypted Debian root with key file on boot partition

I'm trying to decrypt the Debian root with a key file stored in the boot partition (decrypted partition). This will break the security, but it doesn't matter now. I have to conclude this successfully ...
4
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0answers
537 views

forgot to luksClose usb persistent partition, is this a problem?

Following the Kali Linux documentation for "Adding USB Persistence with LUKS Encryption", I created a persistent partition and encrypted the volume with: cryptsetup --verbose --verify-passphrase ...
4
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0answers
269 views

How to use a samba login to mount a luks container?

Our server has an (dm-crypt/LUKS) encrypted project directory which is currently mounted via SSH before its samba share can be accessed - and obviously no one remembers to unmount it afterwards. ...
3
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3answers
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How can I get a HASH of the LUKS master key?

From: https://code.google.com/p/cryptsetup/wiki/FrequentlyAskedQuestions 6.15 Can I clone a LUKS container? You can, but it breaks security, because the cloned container has the same ...
3
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1answer
308 views

How can the root file system be accessed to launch cryptsetup to allow access to the root file system?

I have got laptop with full disk encryption. There is a /boot partion which is not encrypted and the other partition /dev/sda5 is. In order to decrypt, it asks me for the passphrase which is then ...
3
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1answer
1k views

Decrypt second encrypted LVM during headless server boot?

I've followed this question https://unix.stackexchange.com/questions/5017/ssh-to-decrypt-encrypted-lvm-during-headless-server-boot and successfully remotely decrypted my root drive. However, I have a ...
3
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1answer
5k views

parted: create new partition

I have a 3TB disk, and I understand I have to use parted if I want to create a partition bigger than 2TB. All right then. parted /dev/sdb (parted) mklabel gpt (parted) mkpart primary ...
3
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1answer
446 views

cryptdisks_start: precheck failed: the device contains a filesystem type crypto_LUKS

I'm trying to use cryptdisks_start to open a LUKS device that is defined in my /etc/crypttab. Unfortunately, the command fails with the following error message: martin ~ # cryptdisks_start ...
3
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2answers
655 views

How can I set a label on a dm-crypt+LUKS container?

I just received a new USB flash drive, and set up 2 encrypted partitions on it. I used dm-crypt (LUKS mode) through cryptsetup. With an additional non-encrypted partition, the drive has the following ...
3
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1answer
170 views

Recover LUKS partition after overwriting first few bytes of LUKS container? System still up!

I have a 1.5 TB partition of data, of which I accidentally overwrote some bytes at the beginning, due to a typo like: ssh somewhere command | dd of=/dev/sda3 // should have used quotes here, dd ...
3
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1answer
447 views

How can move a LUKS container from the middle of a partition to the beginning?

For the tl;dr, skip to the bottom. I have a dual-boot setup with Mac OS X at the beginning of my drive and three GNU/Linux partitions at the end of the drive. I don't have the relevant machine on ...