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GoCryptFS [](https://travis-ci.org/rfjakob/gocryptfs) 
==============
An encrypted overlay filesystem written in Go.
gocryptfs is built on top the excellent
[go-fuse](https://github.com/hanwen/go-fuse) FUSE library and its
LoopbackFileSystem API.
This project was inspired by [EncFS](https://github.com/vgough/encfs)
and strives to fix its security issues (see EncFS tickets 9, 13, 14, 16).
For details on the security of gocryptfs see the
[SECURITY.md](Documentation/SECURITY.md) document.
Current Status
--------------
Beta. You are advised to keep a backup of your data outside of gocryptfs, in
addition to storing the *master key* in a safe place (the master key is printed
when mounting).
That said, I am dogfooding on gocryptfs for some time now. In fact, all gocryptfs
development happens inside a mounted gocryptfs filesystem, with no issues so far.
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 30 seconds and requires FUSE
as it mounts several test filesystems.
In addition, I have ported `xfstests` to FUSE, the result is the
[fuse-xfstests](https://github.com/rfjakob/fuse-xfstests) project. gocryptfs
passes the "generic" tests with one exception, results: [XFSTESTS.md](Documentation/XFSTESTS.md)
A lot of work has gone into this. The testing has found bugs in gocryptfs
as well as in go-fuse.
The one exception is generic/035, see [go-fuse issue 55](https://github.com/hanwen/go-fuse/issues/55)
for details. While this is a POSIX violation, I do not see any real-world impact.
Install
-------
$ go get github.com/rfjakob/gocryptfs
Use
---
Quickstart:
$ mkdir cipher plain
$ $GOPATH/bin/gocryptfs --init cipher
[...]
$ $GOPATH/bin/gocryptfs cipher plain
[...]
$ echo test > plain/test.txt
$ ls -l cipher
total 8
-rw-rw-r--. 1 user user 33 7. Okt 23:23 0ao8Hyyf1A-A88sfNvkUxA==
-rw-rw-r--. 1 user user 233 7. Okt 23:23 gocryptfs.conf
$ fusermount -u plain
See [MANPAGE.md](Documentation/MANPAGE.md) for a description of available options. If you already
have gocryptfs installed, run `./MANPAGE-render.bash` to bring up the rendered manpage in
the 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)
Performance
-----------
gocryptfs uses openssl through
[spacemonkeygo/openssl](https://github.com/spacemonkeygo/openssl)
for a 3x speedup compared to Go's builtin AES-GCM implementation (see
[go-vs-openssl.md](openssl_benchmark/go-vs-openssl.md) for details).
Run `./benchmark.bash` to run the benchmarks.
The output should look like this:
./benchmark.bash
gocryptfs v0.3.1-30-gd69e0df-dirty; on-disk format 2
PASS
BenchmarkStreamWrite-2 100 12246070 ns/op 85.63 MB/s
BenchmarkStreamRead-2 200 9125990 ns/op 114.90 MB/s
BenchmarkCreate0B-2 10000 101284 ns/op
BenchmarkCreate1B-2 10000 178356 ns/op 0.01 MB/s
BenchmarkCreate100B-2 5000 361014 ns/op 0.28 MB/s
BenchmarkCreate4kB-2 5000 375035 ns/op 10.92 MB/s
BenchmarkCreate10kB-2 3000 491071 ns/op 20.85 MB/s
ok github.com/rfjakob/gocryptfs/integration_tests 17.216s
Changelog
---------
v0.5 (in progress)
* **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 version 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
* 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
* **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
* Replace bash daemonization wrapper with native Go implementation
* Better user feedback on mount failures
v0.1
* First release
* On-disk format 0
See https://github.com/rfjakob/gocryptfs/tags for the release dates and associated
git tags.
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