ecryptfs(7) eCryptfs ecryptfs(7)NAME
eCryptfs - an enterprise-class cryptographic filesystem for linux
SYNOPSIS
mount -tecryptfs [SRC DIR] [DST DIR] -o [OPTIONS]
DESCRIPTION
eCryptfs is a POSIX-compliant enterprise-class stacked cryptographic
filesystem for Linux. It is derived from Erez Zadok's Cryptfs, imple‐
mented through the FiST framework for generating stacked filesystems.
eCryptfs extends Cryptfs to provide advanced key management and policy
features. eCryptfs stores cryptographic metadata in the header of each
file written, so that encrypted files can be copied between hosts; the
file will be decryptable with the proper key, and there is no need to
keep track of any additional information aside from what is already in
the encrypted file itself. Think of eCryptfs as a sort of "gnupgfs."
OPTIONS
STANDARD OPTIONS
key=(keytype):[KEY MODULE OPTIONS]
Specify the type of key to be used when mounting eCryptfs.
ecryptfs_cipher=(cipher)
Specify the symmetric cipher to be used on a per file basis
ecryptfs_key_bytes=(key_bytes)
Specify the keysize to be used with the selected cipher. If the
cipher only has one keysize the keysize does not need to be
specified.
ecryptfs_passthrough
Allows for non-eCryptfs files to be read and written from within
an eCryptfs mount. This option is turned off by default.
no_sig_cache
Do not check the mount key signature against the values in the
user's ~/.ecryptfs/sig-cache.txt file. This is useful for such
things as non-interactive setup scripts, so that the mount
helper does not stop and prompt the user in the event that the
key sig is not in the cache.
ecryptfs_encrypted_view
This option, when set, will have eCryptfs return the encrypted
versions of the lower files, rather than decrypt encrypted files
and return the decrypted data from the lower files. This options
is useful for such things as backup utilities.
ecryptfs_xattr
Store the metadata in the extended attribute of the lower files
rather than the header region of the lower files.
KEY MODULE OPTIONS
Parameters that apply to individual key modules have the alias
for the key module in the prefix of the parameter name. Key mod‐
ules are pluggable, and which key modules are available on any
given system is dependent upon whatever happens to be installed
in /usr/lib*/ecryptfs/. By default, this includes, at a minimum,
"passphrase" and "openssl."
passphrase_passwd=(passphrase)
The actual password is password. Since the password is visible
to utilities (like ps under Unix) this form should only be used
where security is not important.
passphrase_passwd_file=(filename)
The password should be specified in a file with
passwd=(passphrase). It is highly reccomended that the file be
stored on a secure medium such as a personal usb key.
passphrase_passwd_fd=(file descriptor)
The password is specified through the specified file descriptor.
passphrase_salt=(hex value)
The salt should be specified as a 16 digit hex value.
openssl_keyfile=(filename)
The filename should be the filename of a file containing an RSA
SSL key.
openssl_passwd_file=(filename)
The password should be specified in a file with passwd=(openssl-
password). It is highly reccomended that the file be stored on a
secure medium such as a personal usb key.
openssl_passwd_fd=(file descriptor)
The password is specified through the specified file descriptor.
openssl_passwd=(password)
The password can be specified on the command line. Since the
password is visible in the process list, it is highly recom‐
mended to use this option only for testing purposes.
EXAMPLE
The following command will layover mount eCryptfs on /secret with a
passphrase contained in a file stored on secure media mounted at
/mnt/secureusb/.
mount -tecryptfs-o
key=passphrase:passphrase_passwd_file=/mnt/secureusb/passwd_file.txt
/secret /secret
Where passwd_file.txt contains the contents
"passphrase_passwd=[passphrase]".
SEE ALSOmount(8)
/usr/share/doc/ecryptfs-utils/ecryptfs-faq.html
http://ecryptfs.sourceforge.net/
NOTES
Do not run eCryptfs in higher verbosity levels unless you are doing so
for the sole purpose of development, since secret values will be writ‐
ten out to the system log in that case. Make certain that your eCryptfs
mount covers all locations where your applications may write sensitive
data. In addition, use dm-crypt to encrypt your swap space with a ran‐
dom key on boot.
BUGS
Please send bug reports to the lead developer, an eCryptfs mailing list
hosted from SourceForge, or to the SourceForge bug tracker for the
eCryptfs project. For kernel bugs, please follow the procedure detailed
in Documentation/oops-tracing.txt to help us figure out what is happen‐
ing.
AUTHOR
This manpage was (re-)written by Dustin Kirkland <kirkland@canoni‐
cal.com> for Ubuntu systems (but may be used by others). Permission is
granted to copy, distribute and/or modify this document under the terms
of the GNU General Public License, Version 2 or any later version pub‐
lished by the Free Software Foundation.
On Debian systems, the complete text of the GNU General Public License
can be found in /usr/share/common-licenses/GPL.
ecryptfs-utils 2008-07-21 ecryptfs(7)
