b97268c948
This field is added for the convenience of users and may help them to identify which gocryptfs version they need to mount a filesystem. The same information is essentially contained in FeatureFlags, but this is more difficult to decode for humans. It is completely ignored programmatically (also by older gocryptfs versions). |
||
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Documentation | ||
integration_tests | ||
internal | ||
stress_tests | ||
.drone.yml | ||
.gitignore | ||
.travis.yml | ||
benchmark-builtin.bash | ||
benchmark.bash | ||
build.bash | ||
checkdir.go | ||
daemonize.go | ||
LICENSE | ||
main.go | ||
masterkey.go | ||
package.bash | ||
password.go | ||
README.md | ||
sendusr1.go | ||
test.bash | ||
TODO.md |
An encrypted overlay filesystem written in Go. Official website: https://nuetzlich.net/gocryptfs
gocryptfs is built on top the excellent go-fuse FUSE library and its LoopbackFileSystem API.
This project was inspired by EncFS and strives to fix its security issues while providing good performance (benchmarks).
For details on the security of gocryptfs see the Security design document.
All tags from v0.4 onward are signed by the gocryptfs signing key. Please check Signed Releases for details.
Current Status
gocryptfs is a young project. While bugs in any software can cause issues, bugs in encryption software can cause catastrophic data loss. Keep a backup of your gocryptfs filesystem and store a copy of your master key (printed on mount) in a safe place. See below for how gocryptfs is tested.
Only Linux is supported at the moment. Help wanted for a Mac OS X port.
Testing
gocryptfs comes with is own test suite that is constantly expanded as features are
added. Run it using ./test.bash
. It takes about 1 minute and requires FUSE
as it mounts several test filesystems.
The stress_tests
directory contains stress tests that run indefinitely.
In addition, I have ported xfstests
to FUSE, the result is the
fuse-xfstests project. gocryptfs
passes the "generic" tests with one exception, results: XFSTESTS.md
A lot of work has gone into this. The testing has found bugs in gocryptfs as well as in the go-fuse library.
Compile
$ go get github.com/rfjakob/gocryptfs
Use
$ mkdir cipher plain
$ $GOPATH/bin/gocryptfs -init cipher
$ $GOPATH/bin/gocryptfs cipher plain
See the Quickstart page for more info.
The MANPAGE.md containes a description of available command-line options.
If you already have gocryptfs installed, run ./MANPAGE-render.bash
to bring up the rendered manpage in
your man pager (requires pandoc).
Storage Overhead
- Empty files take 0 bytes on disk
- 18 byte file header for non-empty files (2 bytes version, 16 bytes random file id)
- 28 bytes of storage overhead per 4kB block (12 byte nonce, 16 bytes auth tag)
file-format.md contains a more detailed description.
Performance
Since version 0.7.2, gocryptfs is as fast as EncFS in the default mode, and significantly faster than EncFS' "paranoia" mode that provides a security level comparable to gocryptfs.
gocryptfs uses OpenSSL through a thin wrapper called stupidgcm
.
This provides a 4x speedup compared to Go's builtin AES-GCM
implementation - see openssl-gcm.md
for details. The use of openssl can disabled on the command-line.
Run ./benchmark.bash
to run gocryptfs' canonical set of
benchmarks that include streaming write, extracting a linux kernel
tarball, recursively listing and finally deleting it. The output will
look like this:
$ ./benchmark.bash
linux-3.0.tar.gz 100%[==========================>] 92,20M 2,96MB/s in 35s
2016-05-04 19:29:20 URL:https://www.kernel.org/pub/linux/kernel/v3.0/linux-3.0.tar.gz
WRITE: 131072000 bytes (131 MB) copied, 1,43137 s, 91,6 MB/s
UNTAR: 23.25
LS: 1.75
RM: 4.42
Changelog
v0.10, 2016-05-30
- Replace
spacemonkeygo/openssl
withstupidgcm
- gocryptfs now has its own thin wrapper to OpenSSL's GCM implementation
called
stupidgcm
. - This should fix the compile issues
people are seeing with
spacemonkeygo/openssl
. It also gets us a 20% performance boost for streaming writes. - Automatically choose between OpenSSL and Go crypto issue #23
- Go 1.6 added an optimized GCM implementation in amd64 assembly that uses AES-NI. This is faster than OpenSSL and is used if available. In all other cases OpenSSL is much faster and is used instead.
-openssl=auto
is the new default- Passing
-openssl=true/false
overrides the autodetection. - Warn but continue anyway if fallocate(2) is not supported by the underlying filesystem, see issue #22
- Enables to use gocryptfs on ZFS and ext3, albeit with reduced out-of-space safety.
- Fix statfs, by @lxp
- Fix a fsstress failure in the go-fuse library.
v0.9, 2016-04-10
- Long file name support
- gocryptfs now supports file names up to 255 characters.
- This is a forwards-compatible change. gocryptfs v0.9 can mount filesystems created by earlier versions but not the other way round.
- Refactor gocryptfs into multiple "internal" packages
- New command-line options:
-longnames
: Enable long file name support (default true)-nosyslog
: Print messages to stdout and stderr instead of syslog (default false)-wpanic
: Make warning messages fatal (used for testing)-d
: Alias for-debug
-q
: Alias for-quiet
v0.8, 2016-01-23
- Redirect output to syslog when running in the background
- New command-line option:
-memprofile
: Write a memory allocation debugging profile the specified file
v0.7.2, 2016-01-19
- Fix performance issue in small file creation
- This brings performance on-par with EncFS paranoia mode, with streaming writes significantly faster
- The actual fix is in the go-fuse library. There are no code changes in gocryptfs.
v0.7.1, 2016-01-09
- Make the
build.bash
script compatible with Go 1.3 - Disable fallocate on OSX (system call not availabe)
- Introduce pre-built binaries for Fedora 23 and Debian 8
v0.7, 2015-12-20
- Extend GCM IV size to 128 bit from Go's default of 96 bit
- This pushes back the birthday bound to make IV collisions virtually impossible
- This is a forwards-compatible change. gocryptfs v0.7 can mount filesystems created by earlier versions but not the other way round.
- New command-line option:
-gcmiv128
: Use 128-bit GCM IVs (default true)
v0.6, 2015-12-08
- Wide-block filename encryption using EME + DirIV
- EME (ECB-Mix-ECB) provides even better security than CBC as it fixes the prefix leak. The used Go EME implementation is https://github.com/rfjakob/eme which is, as far as I know, the first implementation of EME in Go.
- This is a forwards-compatible change. gocryptfs v0.6 can mount filesystems created by earlier versions but not the other way round.
- New command-line option:
-emenames
: Enable EME filename encryption (default true)
v0.5.1, 2015-12-06
- Fix a rename regression caused by DirIV and add test case
- Use fallocate to guard against out-of-space errors
v0.5, 2015-12-04
- Stronger filename encryption: DirIV
- Each directory gets a random 128 bit file name IV on creation,
stored in
gocryptfs.diriv
- This makes it impossible to identify identically-named files across directories
- A single-entry IV cache brings the performance cost of DirIV close to zero for common operations (see performance.txt)
- This is a forwards-compatible change. gocryptfs v0.5 can mount filesystems created by earlier versions but not the other way round.
- New command-line option:
-diriv
: Use the new per-directory IV file name encryption (default true)-scryptn
: allows to set the scrypt cost parameter N. This option can be used for faster mounting at the cost of lower brute-force resistance. It was mainly added to speed up the automated tests.
v0.4, 2015-11-15
- New command-line options:
-plaintextnames
: disables filename encryption, added on user request-extpass
: calls an external program for prompting for the password-config
: allows to specify a custom gocryptfs.conf path- Add
FeatureFlags
gocryptfs.conf paramter - This is a config format change, hence the on-disk format is incremented
- Used for ext4-style filesystem feature flags. This should help avoid future
format changes. The first user is
-plaintextnames
. - On-disk format 2
v0.3, 2015-11-01
- Add a random 128 bit file header to authenticate file->block ownership
- This is an on-disk-format change
- On-disk format 1
v0.2, 2015-10-11
- Replace bash daemonization wrapper with native Go implementation
- Better user feedback on mount failures
v0.1, 2015-10-07
- First release
- On-disk format 0