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 argu-
ment 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 argu-
ment 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 AT google.com>, Ildar Muslukhov <muslukhovi AT gmail.com>,
and Theodore Ts'o <tytso AT mit.edu>
SEE ALSO
keyctl(1), mke2fs(8), mount(8).
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