390 lines
17 KiB
Markdown
390 lines
17 KiB
Markdown
[](https://nuetzlich.net/gocryptfs/)
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[](https://travis-ci.org/rfjakob/gocryptfs)
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[](LICENSE)
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[](https://goreportcard.com/report/github.com/rfjakob/gocryptfs)
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An encrypted overlay filesystem written in Go.
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Official website: https://nuetzlich.net/gocryptfs (Markdown [source](https://github.com/rfjakob/gocryptfs-website/tree/master/docs))
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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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([benchmarks](https://nuetzlich.net/gocryptfs/comparison/#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/)
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for details.
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Current Status
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--------------
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gocryptfs has reached version 1.0 on July 17, 2016. It has gone through
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hours and hours of stress (fsstress, extractloop.bash) and correctness
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testing (xfstests). It is now considered ready for general consumption.
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The old principle still applies: Important data should have a backup.
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Also, keep a copy of your master key (printed on mount) in a safe place.
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This allows you to access the data even if the gocryptfs.conf config
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file is damaged or you lose the password.
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The security of gocryptfs has been audited in March 3, 2017. The audit
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is available [here (defuse.ca)](https://defuse.ca/audits/gocryptfs.htm).
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Platforms
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---------
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Linux is gocryptfs' native platform.
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Experimental Mac OS X support is available, check out
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[ticket #15](https://github.com/rfjakob/gocryptfs/issues/15) for
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details.
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For Windows, an independent C++ reimplementation has been started:
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[cppcryptfs](https://github.com/bailey27/cppcryptfs)
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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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The `stress_tests` directory contains stress tests that run indefinitely.
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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 the go-fuse library.
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Compile
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-------
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$ go get -d github.com/rfjakob/gocryptfs
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$ cd $(go env GOPATH)/src/github.com/rfjakob/gocryptfs
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$ ./build.bash
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build.bash needs the OpenSSL headers installed (Debian: `apt install libssl-dev`,
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Fedora: `dnf install openssl-devel`). Alternatively, you can compile
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without OpenSSL using
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$ ./build-without-openssl.bash
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Use
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---
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$ mkdir cipher plain
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$ ./gocryptfs -init cipher
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$ ./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) describes all available command-line options.
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Graphical Interface
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-------------------
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The [SiriKali](https://mhogomchungu.github.io/sirikali/) project supports
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gocryptfs and runs on Linux and OSX.
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[cppcryptfs](https://github.com/bailey27/cppcryptfs) on Windows provides
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its own GUI.
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Stable CLI ABI
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--------------
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If you want to call gocryptfs from your app or script, see
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[CLI_ABI.md](Documentation/CLI_ABI.md) for the official stable
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ABI. This ABI is regression-tested by the test suite.
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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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* 32 bytes of storage overhead per 4kB block (16 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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v1.4 (not yet released)
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* Add `force_owner` option to allow files to be presented as owned by a
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different user or group from the user running gocryptfs. Please see caveats
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and guidance in the man page before using this functionality.
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* Increase open file limit to 4096 ([#82](https://github.com/rfjakob/gocryptfs/issues/82)).
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* Implement path decryption via ctlsock ([#84](https://github.com/rfjakob/gocryptfs/issues/84)).
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Previously, decryption was only implemented for reverse mode. Now both
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normal and reverse mode support both decryption and encryption of
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paths via ctlsock.
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* Add more specific exit codes for the most common failure modes,
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documented in [CLI_ABI.md](Documentation/CLI_ABI.md)
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* Reverse mode: make sure hard-linked files always return the same
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ciphertext [commit](https://github.com/rfjakob/gocryptfs/commit/9ecf2d1a3f69e3d995012073afe3fc664bd928f2)
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* Display a shorter, friendlier help text by default.
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v1.3, 2017-04-29
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* **Use HKDF to derive separate keys for GCM and EME**
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* New feature flag: `HKDF` (enabled by default)
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* This is a forwards-compatible change. gocryptfs v1.3 can mount
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filesystems created by earlier versions but not the other way round.
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* Enable Raw64 filename encoding by default (gets rid of trailing `==` characters)
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* Drop Go 1.4 compatibility. You now need Go 1.5 (released 2015-08-19)
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or higher to build gocryptfs.
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* Add `-serialize_reads` command-line option
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* This can greatly improve performance on storage
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that is very slow for concurrent out-of-order reads. Example:
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Amazon Cloud Drive ([#92](https://github.com/rfjakob/gocryptfs/issues/92))
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* Reject file-header-only files
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([#90 2.2](https://github.com/rfjakob/gocryptfs/issues/90),
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[commit](https://github.com/rfjakob/gocryptfs/commit/14038a1644f17f50b113a05d09a2a0a3b3e973b2))
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* Increase max password size to 2048 bytes ([#93](https://github.com/rfjakob/gocryptfs/issues/93))
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* Use stable 64-bit inode numbers in reverse mode
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* This may cause problems for very old 32-bit applications
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that were compiled without Large File Support.
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* Passing "--" now also blocks "-o" parsing
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v1.2.1, 2017-02-26
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* Add an integrated speed test, `gocryptfs -speed`
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* Limit password size to 1000 bytes and reject trailing garbage after the newline
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* Make the test suite work on [Mac OS X](https://github.com/rfjakob/gocryptfs/issues/15)
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* Handle additional corner cases in `-ctlsock` path sanitization
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* Use dedicated exit code 12 on "password incorrect"
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v1.2, 2016-12-04
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* Add a control socket interface. Allows to encrypt and decrypt filenames.
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For details see [backintime#644](https://github.com/bit-team/backintime/issues/644#issuecomment-259835183).
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* New command-line option: `-ctlsock`
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* Under certain circumstances, concurrent truncate and read could return
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an I/O error. This is fixed by introducing a global open file table
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that stores the file IDs
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([commit](https://github.com/rfjakob/gocryptfs/commit/0489d08ae21107990d0efd0685443293aa26b35f)).
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* Coalesce 4kB ciphertext block writes up to the size requested through
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the write FUSE call
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([commit with benchmarks](https://github.com/rfjakob/gocryptfs/commit/024511d9c71558be4b1169d6bb43bd18d65539e0))
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* Add `-noprealloc` command-line option
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* Greatly speeds up writes on Btrfs
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([#63](https://github.com/rfjakob/gocryptfs/issues/63))
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at the cost of reduced out-of-space robustness.
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* This is a workaround for Btrfs' slow fallocate(2)
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* Preserve owner for symlinks an device files (fixes bug [#64](https://github.com/rfjakob/gocryptfs/issues/64))
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* Include rendered man page `gocryptfs.1` in the release tarball
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v1.1.1, 2016-10-30
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* Fix a panic on setting file timestamps ([go-fuse#131](https://github.com/hanwen/go-fuse/pull/131))
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* Work around an issue in tmpfs that caused a panic in xfstests generic/075
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([gocryptfs#56](https://github.com/rfjakob/gocryptfs/issues/56))
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* Optimize NFS streaming writes
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([commit](https://github.com/rfjakob/gocryptfs/commit/a08d55f42d5b11e265a8617bee16babceebfd026))
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v1.1, 2016-10-19
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* **Add reverse mode ([#19](https://github.com/rfjakob/gocryptfs/issues/19))**
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* AES-SIV (RFC5297) encryption to implement deterministic encryption
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securely. Uses the excellent
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[jacobsa/crypto](https://github.com/jacobsa/crypto) library.
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The corresponding feature flag is called `AESSIV`.
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* New command-line options: `-reverse`, `-aessiv`
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* Filesystems using reverse mode can only be mounted with gocryptfs v1.1
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and later.
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* The default, forward mode, stays fully compatible with older versions.
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Forward mode will keep using GCM because it is much faster.
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* Accept `-o foo,bar,baz`-style options that are passed at the end of
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the command-line, like mount(1) does. All other options must still
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precede the passed paths.
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* This allows **mounting from /etc/fstab**. See
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[#45](https://github.com/rfjakob/gocryptfs/issues/45) for details.
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* **Mounting on login using pam_mount** works as well. It is
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[described in the wiki](https://github.com/rfjakob/gocryptfs/wiki/Mounting-on-login-using-pam_mount).
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* To prevent confusion, the old `-o` option had to be renamed. It is now
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called `-ko`. Arguments to `-ko` are passed directly to the kernel.
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* New `-passfile` command-line option. Provides an easier way to read
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the password from a file. Internally, this is equivalent to
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`-extpass "/bin/cat FILE"`.
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* Enable changing the password when you only know the master key
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([#28](https://github.com/rfjakob/gocryptfs/issues/28))
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v1.0, 2016-07-17
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* Deprecate very old filesystems, stage 3/3
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* Filesystems created by v0.6 can no longer be mounted
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* Drop command-line options `-gcmiv128`, `-emenames`, `-diriv`. These
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are now always enabled.
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* Add fallocate(2) support
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* New command-line option `-o`
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* Allows to pass mount options directly to the kernel
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* Add support for device files and suid binaries
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* Only works when running as root
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* Must be explicitely enabled by passing "-o dev" or "-o suid" or "-o suid,dev"
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* Experimental Mac OS X support. See
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[ticket #15](https://github.com/rfjakob/gocryptfs/issues/15) for details.
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v0.12, 2016-06-19
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* Deprecate very old filesystems, stage 2/3
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* Filesystems created by v0.6 and older can only be mounted read-only
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* A [message](https://github.com/rfjakob/gocryptfs/blob/v0.12/internal/configfile/config_file.go#L120)
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explaining the situation is printed as well
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* New command line option: `-ro`
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* Mounts the filesystem read-only
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* Accept password from stdin as well ([ticket #30](https://github.com/rfjakob/gocryptfs/issues/30))
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v0.11, 2016-06-10
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* Deprecate very old filesystems, stage 1/3
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* Filesystems created by v0.6 and older can still be mounted but a
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[warning](https://github.com/rfjakob/gocryptfs/blob/v0.11/internal/configfile/config_file.go#L120)
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is printed
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* See [ticket #29](https://github.com/rfjakob/gocryptfs/issues/29) for details and
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join the discussion
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* Add rsync stress test "pingpong-rsync.bash"
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* Fix chown and utimens failures that caused rsync to complain
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* Build release binaries with Go 1.6.2
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* Big speedup for CPUs with AES-NI, see [ticket #23](https://github.com/rfjakob/gocryptfs/issues/23)
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v0.10, 2016-05-30
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* **Replace `spacemonkeygo/openssl` with `stupidgcm`**
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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`. It also gets us
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a 20% performance boost for streaming writes.
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* **Automatically choose between OpenSSL and Go crypto** [issue #23](https://github.com/rfjakob/gocryptfs/issues/23)
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* Go 1.6 added an optimized GCM implementation in amd64 assembly that uses AES-NI.
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This is faster than OpenSSL and is used if available. In all other
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cases OpenSSL is much faster and is used instead.
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* `-openssl=auto` is the new default
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* Passing `-openssl=true/false` overrides the autodetection.
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* Warn but continue anyway if fallocate(2) is not supported by the
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underlying filesystem, see [issue #22](https://github.com/rfjakob/gocryptfs/issues/22)
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* Enables to use gocryptfs on ZFS and ext3, albeit with reduced out-of-space safety.
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* [Fix statfs](https://github.com/rfjakob/gocryptfs/pull/27), by @lxp
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* Fix a fsstress [failure](https://github.com/hanwen/go-fuse/issues/106)
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in the go-fuse library.
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v0.9, 2016-04-10
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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, 2016-01-23
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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, 2016-01-19
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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, 2016-01-09
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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, 2015-12-20
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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, 2015-12-08
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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, 2015-12-06
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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, 2015-12-04
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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, 2015-11-15
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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, 2015-11-01
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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, 2015-10-11
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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, 2015-10-07
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* First release
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* On-disk format 0
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