208 lines
8.0 KiB
Markdown
208 lines
8.0 KiB
Markdown
[](https://nuetzlich.net/gocryptfs/) [](https://travis-ci.org/rfjakob/gocryptfs) 
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==============
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An encrypted overlay filesystem written in Go.
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Official website: https://nuetzlich.net/gocryptfs
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gocryptfs is built on top the excellent
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[go-fuse](https://github.com/hanwen/go-fuse) FUSE library and its
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LoopbackFileSystem API.
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This project was inspired by EncFS and strives to fix its security
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issues while providing good performance.
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For details on the security of gocryptfs see the
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[Security](https://nuetzlich.net/gocryptfs/security/) design document.
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All tags from v0.4 onward are signed by the *gocryptfs signing key*.
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Please check [Signed Releases](https://nuetzlich.net/gocryptfs/releases/) for
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details.
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Current Status
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--------------
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gocryptfs is a young project. While bugs in any software can cause issues,
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bugs in encryption software can cause catastrophic data loss. Keep a backup
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of your gocryptfs filesystem *and* store a copy of your master key (printed
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on mount) in a safe place.
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Only Linux is supported at the moment. [Help wanted for a Mac OS X port.](https://github.com/rfjakob/gocryptfs/issues/15)
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Testing
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-------
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gocryptfs comes with is own test suite that is constantly expanded as features are
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added. Run it using `./test.bash`. It takes about 1 minute and requires FUSE
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as it mounts several test filesystems.
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In addition, I have ported `xfstests` to FUSE, the result is the
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[fuse-xfstests](https://github.com/rfjakob/fuse-xfstests) project. gocryptfs
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passes the "generic" tests with one exception, results: [XFSTESTS.md](Documentation/XFSTESTS.md)
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A lot of work has gone into this. The testing has found bugs in gocryptfs
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as well as in go-fuse.
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The one exception is generic/035, see [go-fuse issue 55](https://github.com/hanwen/go-fuse/issues/55)
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for details. While this is a POSIX violation, I do not see any real-world impact.
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Compile
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-------
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$ go get github.com/rfjakob/gocryptfs
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Use
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---
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$ mkdir cipher plain
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$ $GOPATH/bin/gocryptfs -init cipher
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$ $GOPATH/bin/gocryptfs cipher plain
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See the [Quickstart](https://nuetzlich.net/gocryptfs/quickstart/) page for more info.
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The [MANPAGE.md](Documentation/MANPAGE.md) containes a description of available command-line options.
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If you already have gocryptfs installed, run `./MANPAGE-render.bash` to bring up the rendered manpage in
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your man pager (requires pandoc).
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Storage Overhead
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----------------
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* Empty files take 0 bytes on disk
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* 18 byte file header for non-empty files (2 bytes version, 16 bytes random file id)
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* 28 bytes of storage overhead per 4kB block (12 byte nonce, 16 bytes auth tag)
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[file-format.md](Documentation/file-format.md) contains a more detailed description.
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Performance
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-----------
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Since version 0.7.2, gocryptfs is as fast as EncFS in the default mode,
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and significantly faster than EncFS' "paranoia" mode that provides
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a security level comparable to gocryptfs.
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gocryptfs uses OpenSSL through a thin wrapper called `stupidgcm`.
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This provides a 4x speedup compared to Go's builtin AES-GCM
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implementation - see [openssl-gcm.md](Documentation/openssl-gcm.md)
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for details. The use of openssl can disabled on the command-line.
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Run `./benchmark.bash` to run gocryptfs' canonical set of
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benchmarks that include streaming write, extracting a linux kernel
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tarball, recursively listing and finally deleting it. The output will
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look like this:
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```
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$ ./benchmark.bash
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linux-3.0.tar.gz 100%[==========================>] 92,20M 2,96MB/s in 35s
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2016-05-04 19:29:20 URL:https://www.kernel.org/pub/linux/kernel/v3.0/linux-3.0.tar.gz
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WRITE: 131072000 bytes (131 MB) copied, 1,43137 s, 91,6 MB/s
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UNTAR: 23.25
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LS: 1.75
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RM: 4.42
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```
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Changelog
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---------
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v0.10-rc1
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* **Drop dependency to `spacemonkeygo/openssl`**
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* gocryptfs now has its own thin wrapper to OpenSSL's GCM implementation
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called `stupidgcm`.
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* This should fix the [compile issues](https://github.com/rfjakob/gocryptfs/issues/21)
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people are seeing with `spacemonkeygo/openssl` and it also gets us
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a 20% performance boost for streaming writes.
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v0.9
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* **Long file name support**
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* gocryptfs now supports file names up to 255 characters.
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* This is a forwards-compatible change. gocryptfs v0.9 can mount filesystems
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created by earlier versions but not the other way round.
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* Refactor gocryptfs into multiple "internal" packages
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* New command-line options:
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* `-longnames`: Enable long file name support (default true)
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* `-nosyslog`: Print messages to stdout and stderr instead of syslog (default false)
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* `-wpanic`: Make warning messages fatal (used for testing)
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* `-d`: Alias for `-debug`
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* `-q`: Alias for `-quiet`
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v0.8
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* Redirect output to syslog when running in the background
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* New command-line option:
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* `-memprofile`: Write a memory allocation debugging profile the specified
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file
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v0.7.2
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* **Fix performance issue in small file creation**
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* This brings performance on-par with EncFS paranoia mode, with streaming writes
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significantly faster
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* The actual [fix](https://github.com/hanwen/go-fuse/commit/c4b6b7949716d13eec856baffc7b7941ae21778c)
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is in the go-fuse library. There are no code changes in gocryptfs.
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v0.7.1
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* Make the `build.bash` script compatible with Go 1.3
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* Disable fallocate on OSX (system call not availabe)
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* Introduce pre-built binaries for Fedora 23 and Debian 8
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v0.7
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* **Extend GCM IV size to 128 bit from Go's default of 96 bit**
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* This pushes back the birthday bound to make IV collisions virtually
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impossible
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* This is a forwards-compatible change. gocryptfs v0.7 can mount filesystems
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created by earlier versions but not the other way round.
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* New command-line option:
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* `-gcmiv128`: Use 128-bit GCM IVs (default true)
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v0.6
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* **Wide-block filename encryption using EME + DirIV**
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* EME (ECB-Mix-ECB) provides even better security than CBC as it fixes
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the prefix leak. The used Go EME implementation is
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https://github.com/rfjakob/eme which is, as far as I know, the first
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implementation of EME in Go.
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* This is a forwards-compatible change. gocryptfs v0.6 can mount filesystems
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created by earlier versions but not the other way round.
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* New command-line option:
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* `-emenames`: Enable EME filename encryption (default true)
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v0.5.1
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* Fix a rename regression caused by DirIV and add test case
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* Use fallocate to guard against out-of-space errors
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v0.5
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* **Stronger filename encryption: DirIV**
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* Each directory gets a random 128 bit file name IV on creation,
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stored in `gocryptfs.diriv`
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* This makes it impossible to identify identically-named files across
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directories
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* A single-entry IV cache brings the performance cost of DirIV close to
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zero for common operations (see performance.txt)
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* This is a forwards-compatible change. gocryptfs v0.5 can mount filesystems
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created by earlier versions but not the other way round.
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* New command-line option:
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* `-diriv`: Use the new per-directory IV file name encryption (default true)
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* `-scryptn`: allows to set the scrypt cost parameter N. This option
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can be used for faster mounting at the cost of lower brute-force
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resistance. It was mainly added to speed up the automated tests.
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v0.4
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* New command-line options:
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* `-plaintextnames`: disables filename encryption, added on user request
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* `-extpass`: calls an external program for prompting for the password
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* `-config`: allows to specify a custom gocryptfs.conf path
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* Add `FeatureFlags` gocryptfs.conf paramter
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* This is a config format change, hence the on-disk format is incremented
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* Used for ext4-style filesystem feature flags. This should help avoid future
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format changes. The first user is `-plaintextnames`.
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* On-disk format 2
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v0.3
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* **Add a random 128 bit file header to authenticate file->block ownership**
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* This is an on-disk-format change
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* On-disk format 1
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v0.2
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* Replace bash daemonization wrapper with native Go implementation
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* Better user feedback on mount failures
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v0.1
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* First release
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* On-disk format 0
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See https://github.com/rfjakob/gocryptfs/tags for the release dates and associated
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git tags.
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