e4crypt(8) — Linux manual page
E4CRYPT(8) System Manager's Manual E4CRYPT(8)
NAME
e4crypt - ext4 file system encryption utility
SYNOPSIS
e4crypt add_key -S [ -k keyring ] [-v] [-q] [ -p pad ] [ path ...
]
e4crypt new_session
e4crypt get_policy path ...
e4crypt set_policy [ -p pad ] policy path ...
DESCRIPTION
e4crypt performs encryption management for ext4 file systems.
COMMANDS
e4crypt add_key [-vq] [-S salt ] [-k keyring ] [ -p pad ] [ path
... ]
Prompts the user for a passphrase and inserts it into the
specified keyring. If no keyring is specified, e4crypt
will use the session keyring if it exists or the user
session keyring if it does not.
The salt argument is interpreted in a number of different
ways, depending on how its prefix value. If the first two
characters are "s:", then the rest of the argument will be
used as an text string and used as the salt value. If the
first two characters are "0x", then the rest of the
argument will be parsed as a hex string as used as the
salt. If the first characters are "f:" then the rest of
the argument will be interpreted as a filename from which
the salt value will be read. If the string begins with a
'/' character, it will similarly be treated as filename.
Finally, if the salt argument can be parsed as a valid
UUID, then the UUID value will be used as a salt value.
The keyring argument specifies the keyring to which the
key should be added.
The pad value specifies the number of bytes of padding
will be added to directory names for obfuscation purposes.
Valid pad values are 4, 8, 16, and 32.
If one or more directory paths are specified, e4crypt will
try to set the policy of those directories to use the key
just added by the add_key command. If a salt was
explicitly specified, then it will be used to derive the
encryption key of those directories. Otherwise a
directory-specific default salt will be used.
e4crypt get_policy path ...
Print the policy for the directories specified on the
command line.
e4crypt new_session
Give the invoking process (typically a shell) a new
session keyring, discarding its old session keyring.
e4crypt set_policy [ -p pad ] policy path ...
Sets the policy for the directories specified on the
command line. All directories must be empty to set the
policy; if the directory already has a policy established,
e4crypt will validate that the policy matches what was
specified. A policy is an encryption key identifier
consisting of 16 hexadecimal characters.
AUTHOR
Written by Michael Halcrow <mhalcrow@google.com>, Ildar Muslukhov
<muslukhovi@gmail.com>, and Theodore Ts'o <tytso@mit.edu>
SEE ALSO
keyctl(1), mke2fs(8), mount(8).
COLOPHON
This page is part of the e2fsprogs (utilities for ext2/3/4
filesystems) project. Information about the project can be found
at ⟨http://e2fsprogs.sourceforge.net/⟩. It is not known how to
report bugs for this man page; if you know, please send a mail to
man-pages@man7.org. This page was obtained from the project's
upstream Git repository
⟨git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git⟩ on
2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-05-20.) 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 improvements to the
information in this COLOPHON (which is not part of the original
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