<img src="https://zboxfs.github.io/zbox/images/logo.svg" alt="ZboxFS Logo" height="96" /> ZboxFS

ZboxFS is a zero-details, privacy-focused in-app file system. Its goal is to help application store files securely, privately and reliably. By encapsulating files and directories into an encrypted repository, it provides a virtual file system and exclusive access to authorised application.

Unlike other system-level file systems, such as [ext4], [XFS] and [Btrfs], which provide shared access to multiple processes, ZboxFS is a file system that runs in the same memory space as the application. It provides access to only one process at a time.

By abstracting IO access, ZboxFS supports a variety of underlying storage layers, including memory, OS file system, RDBMS and key-value object store.

Disclaimer

ZboxFS is under active development, we are not responsible for any data loss or leak caused by using it. Always back up your files and use at your own risk!

Features

• Everything is encrypted :lock:, including metadata and directory structure, no knowledge can be leaked to underlying storage
• State-of-the-art cryptography: AES-256-GCM (hardware), XChaCha20-Poly1305, Argon2 password hashing and etc., powered by [libsodium]
• Support varieties of underlying storages, including memory, OS file system, RDBMS, Key-value object store and more
• Files and directories are packed into same-sized blocks to eliminate metadata leakage
• Content-based data chunk deduplication and file-based deduplication
• Data compression using [LZ4] in fast mode, optional
• Data integrity is guaranteed by authenticated encryption primitives (AEAD crypto)
• File contents versioning
• Copy-on-write (COW :cow:) semantics
• ACID transactional operations
• Built with [Rust] :hearts:

Comparison

Many OS-level file systems support encryption, such as [EncFS], [APFS] and [ZFS]. Some disk encryption tools also provide virtual file system, such as [TrueCrypt], [LUKS] and [VeraCrypt].

This diagram shows the difference between ZboxFS and them.

Below is the feature comparison list.

| | ZboxFS | OS-level File Systems | Disk Encryption Tools | | --------------------------- | ------------------------ | ------------------------ | ------------------------ | | Encrypts file contents | :heavy_check_mark: | partial | :heavy_check_mark: | | Encrypts file metadata | :heavy_check_mark: | partial | :heavy_check_mark: | | Encrypts directory | :heavy_check_mark: | partial | :heavy_check_mark: | | Data integrity | :heavy_check_mark: | partial | :heavy_multiplication_x: | | Shared access for processes | :heavy_multiplication_x: | :heavy_check_mark: | :heavy_check_mark: | | Deduplication | :heavy_check_mark: | :heavy_multiplication_x: | :heavy_multiplication_x: | | Compression | :heavy_check_mark: | partial | :heavy_multiplication_x: | | Content versioning | :heavy_check_mark: | :heavy_multiplication_x: | :heavy_multiplication_x: | | COW semantics | :heavy_check_mark: | partial | :heavy_multiplication_x: | | ACID Transaction | :heavy_check_mark: | :heavy_multiplication_x: | :heavy_multiplication_x: | | Varieties of storages | :heavy_check_mark: | :heavy_multiplication_x: | :heavy_multiplication_x: | | API access | :heavy_check_mark: | through VFS | through VFS | | Symbolic links | :heavy_multiplication_x: | :heavy_check_mark: | depends on inner FS | | Users and permissions | :heavy_multiplication_x: | :heavy_check_mark: | :heavy_check_mark: | | FUSE support | :heavy_multiplication_x: | :heavy_check_mark: | :heavy_check_mark: | | Linux and macOS support | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | | Windows support | :heavy_check_mark: | partial | :heavy_check_mark: |

Supported Storage

ZboxFS supports a variety of underlying storages. Memory storage is enabled by default. All the other storages can be enabled individually by specifying its corresponding Cargo feature when building ZboxFS.

| Storage | URI identifier | Cargo Feature | | ------------------ | --------------- | ------------------- | | Memory | "mem://" | N/A | | OS file system | "file://" | storage-file | | SQLite | "sqlite://" | storage-sqlite | | Redis | "redis://" | storage-redis | | Zbox Cloud Storage | "zbox://" | storage-zbox-native |

* Visit zbox.io to learn more about Zbox Cloud Storage.

Specs

| Algorithm and data structure | Value | | ------------------------------------ | --------------------------------- | | Authenticated encryption | AES-256-GCM or XChaCha20-Poly1305 | | Password hashing | Argon2 | | Key derivation | BLAKE2B | | Content dedup | Rabin rolling hash | | File dedup | Merkle tree | | Index structure | Log-structured merge-tree | | Compression | LZ4 in fast mode |

Limits

| Limit | Value | | ----------------------------------------- | ---------------------------- | | Data block size | 8 KiB | | Maximum encryption frame size | 128 KiB | | Super block size | 8 KiB | | Maximum filename length | No limit | | Allowable characters in directory entries | Any UTF-8 character except / | | Maximum pathname length | No limit | | Maximum file size | 16 EiB | | Maximum repo size | 16 EiB | | Max number of files | No limit |

Metadata

| Metadata | Value | | ----------------------------------------- | ---------------------------- | | Stores file owner | No | | POSIX file permissions | No | | Creation timestamps | Yes | | Last access / read timestamps | No | | Last change timestamps | Yes | | Access control lists | No | | Security | Integrated with crypto | | Extended attributes | No |

Capabilities

| Capability | Value | | ----------------------------------------- | ---------------------------- | | Hard links | No | | Symbolic links | No | | Case-sensitive | Yes | | Case-preserving | Yes | | File Change Log | By content versioning | | Filesystem-level encryption | Yes | | Data deduplication | Yes | | Data checksums | Integrated with crypto | | Offline grow | No | | Online grow | Auto | | Offline shrink | No | | Online shrink | Auto |

Allocation and layout policies

| Feature | Value | | --------------------------- | --------------------------------- | | Address allocation scheme | Append-only, linear address space | | Sparse files | No | | Transparent compression | Yes | | Extents | No | | Copy on write | Yes |

Storage fragmentation

| Fragmentation | Value | | ---------------------------- | ---------------------------- | | Memory storage | No | | File storage | fragment unit size < 32 MiB | | RDBMS storage | No