systemd-cryptsetup@.service is a service responsible for setting up
encrypted block devices. It is instantiated for each device that
requires decryption for access.
systemd-cryptsetup@.service will ask for hard disk passwords via the
password agent logic[1], in order to query the user for the password
using the right mechanism at boot and during runtime.
At early boot and when the system manager configuration is reloaded,
/etc/crypttab is translated into systemd-cryptsetup@.service units by
systemd-cryptsetup-generator(8).
In order to unlock a volume a password or binary key is required.
systemd-cryptsetup@.service tries to acquire a suitable password or
binary key via the following mechanisms, tried in order:
1. If a key file is explicitly configured (via the third column in
/etc/crypttab), a key read from it is used. If a PKCS#11 token is
configured (using the pkcs11-uri= option) the key is decrypted
before use.
2. If no key file is configured explicitly this way, a key file is
automatically loaded from /etc/cryptsetup-keys.d/volume.key and
/run/cryptsetup-keys.d/volume.key, if present. Here too, if a
PKCS#11 token is configured, any key found this way is decrypted
before use.
3. If the try-empty-password option is specified it is then
attempted to unlock the volume with an empty password.
4. The kernel keyring is then checked for a suitable cached password
from previous attempts.
5. Finally, the user is queried for a password, possibly multiple
times.
If no suitable key may be acquired via any of the mechanisms
describes above, volume activation fails.
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-11.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
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of the original manual page), send a mail to man-pages@man7.org
systemd 246 SYSTEMD-CRYPTSETUP@.SERVICE(8)