https://github.com/netheril96/securefs
Filesystem in userspace (FUSE) with transparent authenticated encryption
https://github.com/netheril96/securefs
authentication cloud crypto cryptography encryption filesystem filesystems fuse fuse-filesystem security
Last synced: about 1 month ago
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Filesystem in userspace (FUSE) with transparent authenticated encryption
- Host: GitHub
- URL: https://github.com/netheril96/securefs
- Owner: netheril96
- License: other
- Created: 2015-04-11T11:48:51.000Z (about 10 years ago)
- Default Branch: master
- Last Pushed: 2024-10-20T06:27:52.000Z (6 months ago)
- Last Synced: 2024-11-04T05:34:34.863Z (6 months ago)
- Topics: authentication, cloud, crypto, cryptography, encryption, filesystem, filesystems, fuse, fuse-filesystem, security
- Language: C++
- Homepage:
- Size: 13.1 MB
- Stars: 742
- Watchers: 30
- Forks: 63
- Open Issues: 22
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
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README
# securefs
`securefs` is a filesystem in userspace (FUSE) with transparent encryption (when writing) and decryption (when reading).
`securefs` mounts a regular directory onto a mount point. The mount point appears as a regular filesystem, where one can read/write/create files, directories and symbolic links. The underlying directory will be automatically updated to contain the encrypted and authenticated contents.
## Motivation
From sensitive financial records to personal diaries and collection of guilty pleasures, we all have something to keep private from prying eyes. Especially when we store our files in the cloud, the company and the NSA may well get their hands upon it. The best protection we can afford ourselves is **cryptography**, the discipline developed by mathematicians and military originally to keep the national secrets.
Security, however, is often at odds with convenience, and people easily grow tired of the hassle and revert to no protection at all. Consider the case of protecting our files either locally or in the cloud: we have to encrypt the files before committing to the cloud and decrypt it every time we need to read and write. Worse still, such actions leave unencrypted traces on our hard drive. If we store data in the cloud, another issue arise: manual encryption and decryption prevent files from being synced efficiently.
`securefs` is intended to make the experience as smooth as possible so that the security and convenience do not conflict. After mounting the virtual filesystem, everything just works™.
## Comparison
There are already many encrypting filesystem in widespread use. Some notable ones are TrueCrypt, FileVault, BitLocker, eCryptFS, encfs, cryfs, rclone and gocryptfs. `securefs` differs from them in that it is the only one with all of the following features:
- [Authenticated encryption](https://en.wikipedia.org/wiki/Authenticated_encryption) (hence secure against chosen ciphertext attacks)
- [Probabilistic encryption](https://en.wikipedia.org/wiki/Probabilistic_encryption) (hence provides semantical security)
- Supported on all major platforms (Mac, Linux, BSDs and Windows)
- Efficient cloud synchronization (not a single preallocated file as container)
- Full 255 bytes long file name components.
- (Optional) File size obfuscation by random padding.
- (Optional) Case insensitive and case preserving filesystem (matching the default behavior of NTFS).
- (Optional) Unicode normalization agnostic filesystem (matching the default behavior of APFS/HFS+)
## Install
[](https://github.com/netheril96/securefs/actions)
### Dependencies
On Windows, we need to separately install [WinFsp](https://winfsp.dev/) and [VC++ redistributable](https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170#visual-studio-2015-2017-2019-and-2022).
On Linux, we need to install `libfuse-dev`/`fuse-devel` package.
On FreeBSD, we need to run `pkg install fusefs-libs`.
On macOS, we need to install [MacFUSE](https://osxfuse.github.io/).
### Binary packages
Download from the Release page.
### Build from source
First you need to install [vcpkg](https://vcpkg.io). Then run `python3 build.py --enable_unit_test`.
### Package managers
#### macOS
Use [homebrew](https://brew.sh).
`brew install netheril96/fuse/securefs-mac`
## Basic usage
_It is recommended to disable or encrypt the swap and hibernation file. Otherwise plaintext and keys stored in the main memory may be written to disk by the OS at any time._
Examples:
```bash
# Help commands
securefs --help
securefs m --help
securefs c --help
# Creation
securefs create ~/Secret # Default parameters
securefs create ~/Secret --keyfile ./mykey # Use keyfile instead of password
securefs c ~/Secret --max-padding 65535 # Randomly pad each file with at most 65535 bytes to obfuscate its size
securefs c ~/Secret --format full # Full mode. See below for the meaning.
securefs c ~/Secret --format full --case insensitive # Like NTFS
securefs c ~/Secret --format full --uninorm insensitive # Like APFS
# Mounting
securefs mount ~/Secret ~/Mount # press Ctrl-C to unmount
securefs mount ~/Secret ~/Mount --keyfile ./mykey # press Ctrl-C to unmount
# Mount in the background (no-op on Windows). Use `umount` to unmount.
securefs m -b ~/Secret ~/Mount --log ~/securefs.thismaycontainsensitiveinformation.log
securefs m --plain-text-names ~/Secret ~/Mount # Do not encrypt the filenames
securefs m ~/Secret Z: # Windows only
# Change password
securefs chpass ~/Secret
```
See the [full command line options](docs/usage.md).
## GUI
[SiriKali](https://mhogomchungu.github.io/sirikali/) is a GUI frontend for securefs (and several other filesystems).
Note: this is informational only. The author of securefs has never tried SiriKali or vetted its code.
## Lite and full mode
There are two categories of filesystem format.
The **lite** format simply encrypts filenames and file contents separately, similar to how `encfs` operates, although with more security.
The **full** format maps files, directory and symlinks in the virtual filesystem all to regular files in the underlying filesystem. The directory structure is flattened and recorded as B-trees in files.
The lite format is the default as it is much faster and features easier conflict resolution, especially when used with DropBox, Google Drive, etc. The full format, however, leaks fewer information about the filesystem hierarchy, runs relatively independent of the features of the underlying filesystem, and is in general more secure.
To request full format, which is no longer the default, run `securefs create --format full`.
## Design and algorithms
See [here](docs/design.md).
## Caveat
If you store `securefs` encrypted files on iCloud Drive, it might cause Spotlight Search on iOS to stop working. It is a bug in iOS, not in `securefs`.
To work around that bug, you can disable the indexing of _Files_ app in Settings -> Siri & Suggestions.
## Crash resistance
If `securefs` exits abnormally, or if the computer suddenly powers down, we have only the following guarantees (assuming the underlying filesystem isn't corrupted)
1. Files not being written will never be corrupted.
2. In lite format, the directory structure and file names will not be corrupted, unless the file name is a [long name](docs/long_name.md).
3. In full format, the directory structure and file names may be corrupted, but the files themselves can be recovered even in this case.