VaultBox

A desktop application for browsing gocryptfs-encrypted vaults without mounting them. All decryption happens in-process memory — no FUSE mount, no temp files on disk, no plaintext exposed to other apps.

Cryptographic compatibility with gocryptfs v2 is verified by cross-validation tests: files encrypted by gocryptfs are decrypted by VaultBox and vice versa.

Warning: This is an experimental project. The cryptographic implementation has not been independently audited. There may be bugs that corrupt data or compromise security. Use at your own risk. Do not rely on this as your only way to access important encrypted data — always keep backups.

Features

Vault Management

• Open and browse gocryptfs v2 encrypted vaults
• Create new encrypted vaults with password strength indicator and master key backup
• Auto-lock after 10 minutes of inactivity
• Zero plaintext on disk — everything stays in memory

File Viewers

• Text editor — CodeMirror 6 with syntax highlighting for 15+ languages, Cmd+S to save; each tab runs in an isolated webview for V8 heap isolation
• Markdown preview — Live split-view rendering with toggle button
• PDF viewer — pdfjs-dist with zoom, fit-width/fit-page, page navigation, scroll tracking
• Image viewer — Inline preview with fullscreen mode, zoom, pan, double-click to toggle
• Media player — Streaming video/audio via vaultmedia:// protocol with HTTP Range support
• Archive viewer — Browse .zip contents with tree view; extract individual files or all to vault/disk
• Hex viewer — Binary inspection with offset/hex/ASCII display
• Files up to 2 GB can be opened in-app; larger files can be exported to disk

File Operations

• Create, rename, copy, move, delete, import, export
• Batch operations — multi-select for Export All, Copy All, Delete All
• Move to folder via right-click context menu with flyout submenu
• Search across decrypted filenames
• Cmd+N to create new file, Cmd+Shift+N for new folder

UI

• Split view — side-by-side file comparison (Alt+click tab for right pane)
• Tab reorder via pointer drag
• File type icons — unique colored SVGs for code, config, markup, audio, archive, shell, PDF
• Image gallery — fullscreen thumbnail strip with keyboard navigation (arrows, Home, End)
• File info panel (Cmd+I) — file type, size, dates, path, image preview
• Custom confirm dialogs for all destructive actions
• ARIA labels, roles, and keyboard navigation across all interactive elements
• Dark theme (gray-950), Tailwind CSS v4

Security Model

VaultBox is designed to keep decrypted data isolated to a single process, unlike gocryptfs FUSE mounts which expose plaintext to all processes via the filesystem.

	gocryptfs FUSE mount	VaultBox
Plaintext access	Any process can open("/mnt/vault/file")	Only VaultBox process
Malware with user privileges	Reads files like normal files	macOS/Linux: blocked by OS
Kernel page cache	Decrypted pages cached by kernel	No kernel cache
Visibility	Mount point visible via mount, df	No mount point

Memory protection

Protection	How	Platform
Isolated webviews	Each text editor tab runs in a separate child webview; closing a tab destroys the entire V8 heap, reclaiming all decrypted content	All
XOR-masked keys	Keys stored as masked = key ⊕ random_mask; unmasked only during crypto operations (microseconds), then re-masked with fresh random pad	All
mlock	All key material and plaintext cache entries pinned in RAM via mlock() / VirtualLock() — never swapped to disk	All
Zeroize on drop	Keys, passwords, decrypted buffers zeroed via volatile writes (zeroize crate) — compiler cannot optimize away	All
GC pressure on close	Tab close and vault lock overwrite editor document content and allocate throwaway buffers to encourage V8 garbage collection	All
Core dumps disabled	setrlimit(RLIMIT_CORE, 0) at startup	Unix
Anti-ptrace	prctl(PR_SET_DUMPABLE, 0) — blocks /proc/pid/mem reads and ptrace attach from same-user processes	Linux

Password handling

Layer	Type	Zeroed after use?
useSecurePassword hook	number[] (mutable ref, not a JS string)	Yes — fill(0) on consume
IPC transport	Uint8Array → number[]	Yes — both zeroed in finally
Rust command handler	Vec<u8> → String for scrypt	Yes — both .zeroize() after KDF

Network isolation

Layer	Mechanism
CSP connect-src	'self' ipc: http://ipc.localhost vaultmedia: — blocks all external HTTP/WebSocket
No plugins with network access	opener plugin removed; only dialog plugin remains
Rust code	No reqwest, hyper, or any HTTP client in dependencies

Filesystem restrictions

Mechanism	What it does
Tauri capabilities	Minimal: core:default + dialog:allow-open + dialog:allow-save only
validate_external_path()	Import/export blocked for /etc, /System, /usr, /bin, /proc, /sys, all hidden directories (.ssh, .gnupg, .aws, .config, etc.)
Vault operations	Path resolution constrained to vault_path — no traversal outside vault directory

Content rendering safety

All vault content is rendered safely — no user-supplied scripts can execute:

Content type	Rendering method	Script execution
HTML, SVG, JSON, TXT	CodeMirror text editor	Impossible — displayed as source code
Markdown preview	Custom renderer with escapeHtml()	Blocked — HTML tags escaped, javascript: links stripped
Images (including SVG)	<img src="vaultmedia://...">	Blocked — browsers don't execute scripts in <img> tags
PDF	pdfjs-dist canvas rendering	Blocked — pdfjs does not execute embedded JS
Archives (.zip)	Metadata parsing only	Impossible — no content rendering

Known limitations

• JavaScript strings are immutable and GC'd, not zeroized — decrypted text in open editor tabs persists in isolated webview JS heap until the tab is closed (destroying the webview)
• On Windows, ReadProcessMemory from a same-user process can read VaultBox memory; XOR masking makes this harder but not impossible for a targeted attacker
• CodeMirror editor maintains internal copies of document content in JS heap (mitigated by isolated webviews — each editor gets its own heap)

Architecture

• Frontend: React 19 + TypeScript + Tailwind CSS 4 + CodeMirror 6 + pdfjs-dist
• Backend: Rust (Tauri v2) handling all crypto operations
• Webviews: Multi-webview architecture (Tauri v2 unstable feature) — each text editor tab runs in a separate child webview for V8 heap isolation
• Crypto: AES-256-GCM (128-bit nonces) content encryption, EME (ECB-Mix-ECB) filename encryption, scrypt + HKDF-SHA256 key derivation
• IPC: Tauri invoke() — in-process, not over network sockets; cross-webview communication via Tauri events
• Media: Custom vaultmedia:// protocol for streaming decrypted video/audio with HTTP Range support

Prerequisites

• Node.js (v18+)
• Rust (stable)
• Tauri v2 prerequisites

Development

npm install
npm run tauri dev

Build

npm run tauri build

The bundled app will be in src-tauri/target/release/bundle/.

Tests

# Rust tests
cd src-tauri
cargo test

# Frontend tests
npm test

362 tests across 8 test suites:

Suite	Tests	What's covered
Unit tests (--lib)	203	AES-256-GCM content encryption (16-byte nonces, 24-byte AAD), EME filename encryption, HKDF key derivation with known vectors, scrypt KDF, config parsing, streaming decryption, vault state management, LRU cache with mlock/zeroize, XOR-masked key storage, core dump prevention
crypto_pure	78	HKDF known vectors from gocryptfs, real vault KDF validation, block size/offset monotonicity, range splitting, content roundtrips (0B–10MB), filename roundtrips (dot names, Unicode, 300-char), AAD format verification, corruption detection, concurrent encrypt/decrypt, performance benchmarks, security edge cases
vault_ops	25	Full vault CRUD on real encrypted structures: create/read/write/rename/delete/copy/search, nested directories, Unicode names, plaintext-not-on-disk verification
memory_security	22	Zeroize verification via raw pointers (decrypt results, derived keys, LockedKey temporaries), mlock lifecycle, key isolation, no plaintext leakage in ciphertext/filenames, scrypt brute-force resistance, XOR-masked key roundtrips
gocryptfs_compat	6	Cross-validation with real gocryptfs binary: VaultBox decrypts gocryptfs-created files, gocryptfs decrypts VaultBox-created files, config/key derivation compatibility
debug_kdf	3	Step-by-step KDF comparison with Go output (scrypt → HKDF → GCM → master key), pure HKDF vector validation
Frontend (Vitest)	25	React component rendering, file store state management, file type detection, viewer selection logic

Fuzz testing

Fuzz targets for crypto modules are in src-tauri/fuzz/. They use cargo-fuzz (libFuzzer) to find panics, crashes, and roundtrip violations.

# Prerequisites
rustup toolchain install nightly
cargo install cargo-fuzz

# Run a fuzz target (from src-tauri/)
cargo +nightly fuzz run fuzz_content_decrypt -- -max_total_time=300

Target	What it fuzzes
fuzz_content_decrypt	Arbitrary bytes → decrypt_file() — no panics or OOM
fuzz_content_roundtrip	encrypt_file(x) → decrypt_file() == x for all inputs
fuzz_filename	Arbitrary strings → filename decrypt + encrypt→decrypt roundtrip
fuzz_eme	EME encrypt→decrypt roundtrip for all block-aligned inputs

Security audit commands

cd src-tauri

# Check dependencies for known vulnerabilities (CVEs)
cargo audit

# Count unsafe blocks in the dependency tree
cargo geiger

# Search for unsafe in VaultBox source (should only be in security/ primitives)
grep -rn "unsafe" src/

Unsafe audit summary (VaultBox source only):

Location	Count	Purpose
security/mlock.rs	4	libc::mlock/munlock system calls
security/coredump.rs	2	libc::setrlimit to disable core dumps
vault/cache.rs	1	read_volatile in tests
security/locked_key.rs	1	read_volatile in tests
crypto/	0	No unsafe in any crypto module

Cross-validation (requires FUSE)

Three tests require macFUSE/FUSE to mount a gocryptfs filesystem:

# Set gocryptfs binary path (or add to PATH):
export GOCRYPTFS_BIN=/path/to/gocryptfs

cargo test --test gocryptfs_compat -- --ignored --nocapture

These tests verify bidirectional compatibility:

• gocryptfs → VaultBox: Create files with gocryptfs mount, decrypt filenames and content with Rust
• VaultBox → gocryptfs: Create files with VaultBox Rust code, mount with gocryptfs and read back

License

MIT