Editing: README.gnupg
Using GnuPG keys for LUKS dm-crypt devices in Debian ==================================================== The Debian cryptsetup package provides the keyscript `decrypt_gnupg` for setups with a GnuPG encrypted LUKS keyfile. The following example assumes that you store the encrypted keyfile in `/etc/keys/cryptkey.gpg`. LUKS device is `/dev/<luks_device>`. First, you'll have to create the encrypted keyfile: dd if=/dev/random bs=1 count=256 | gpg --no-options --no-random-seed-file \ --no-default-keyring --keyring /dev/null --secret-keyring /dev/null \ --trustdb-name /dev/null --symmetric --output /etc/keys/cryptkey.gpg Next the LUKS device needs to be formated with the key. For that, the `decrypt_gnupg` keyscript can be used: /lib/cryptsetup/scripts/decrypt_gnupg /etc/keys/cryptkey.gpg | \ cryptsetup --key-file=- luksFormat /dev/<luks_device> In order to unlock the encrypted LUKS device automatically during boot process, add the following to `/etc/crypttab`: cdev1 /dev/<luks_device> /etc/keys/cryptkey.gpg luks,discard,keyscript=decrypt_gnupg Decrypting the keyfile at initramfs stage ----------------------------------------- If the device is to be unlocked at initramfs stage (such as for the root FS or the resume device), the provided initramfs hooks should do all additionally required work for you when the initramfs is created or updated. Be warned though, that for such devices the GnuPG encrypted key is copied to the initramfs by the initramfs cryptgnupg hook. If you don't want this, you should take a look at the initramfs cryptgnupg hook, which is located at `/usr/share/initramfs-tools/hooks/cryptgnupg`. -- Jonas Meurer <jonas@freesources.org> Thu, 04 Mar 2010 17:31:40 +0100 -- Guilhem Moulin <guilhem@guilhem.org> Sat, 17 Sep 2016 16:14:41 +0200
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