Neuron Encrypt

Neuron Encrypt is a local file encryption app that keeps your files private. No accounts, no internet, no cloud — everything happens on your device.

Security
• AES-256-GCM-SIV (RFC 8452) — nonce-misuse resistant authenticated encryption
• Argon2id key derivation (256 MiB memory cost) — GPU/ASIC resistant
• HKDF-SHA512 key expansion with per-version domain separation
• VAULTX04 format with authenticated header (AAD on every chunk)
• 100% Safe Rust core — zero unsafe blocks in the crypto library
• Zero internet permissions, zero storage permissions (uses SAF)
• Keys and plaintext wiped from RAM with Zeroizing on drop

Features
• Encrypt any file to a .vx2 container
• Decrypt .vx2 files back to original
• Batch processing — queue multiple files with one passphrase
• Auto-detects encrypt vs decrypt mode from file magic bytes
• Cancel mid-operation (within one 1 MiB chunk)
• Password strength meter
• Secure wipe original file after encryption (with confirmation)
• Open source (GPLv3)

How it works
1. Select a file (or drop one from your file manager)
2. Enter a strong passphrase
3. Tap ENCRYPT — your file is encrypted to .vx2 beside the original
4. Optionally wipe the original file

Your passphrase never leaves the device. There is no recovery — if you forget the passphrase, your files are gone. This is by design.

Privacy
• No analytics, no tracking, no telemetry
• No network permissions in the APK
• No storage permissions (uses Android Storage Access Framework)
• No backup (android:allowBackup=false)
• Source code available at gitlab.com/theredhacker0345/neuron-encrypt

Technical specs
• Cipher: AES-256-GCM-SIV with BE32 streaming (1 MiB chunks)
• KDF: Argon2id (m=256 MiB, t=3, p=4, 64-byte output)
• RNG: OS CSPRNG (OsRng via getrandom)
• Min Android: 7.0 (API 24)
• ABIs: arm64-v8a, armeabi-v7a, x86_64, x86

v2.1.2 — Fixed empty output files from Drive/cloud storage: the app no longer detaches the file descriptor before encryption finishes, so files from remote providers (e.g. Google Drive) come out intact instead of 0 bytes. Also enabled predictive-back navigation and bumped versionCode to 5.