Fast, calm, local file sharing for Android. Flutter UI, native C++ transfer engine.
Signed APKs are published on the Releases page by CI on every push to main. Most phones want the arm64-v8a APK. The version is major.minor.<build number>, so a higher number is always newer.
| Path | What |
|---|---|
android/app/src/main/cpp/engine.* |
Transfer engine: any number of concurrent send/receive sessions; per session N parallel TCP streams fed from one chunk queue; per-stream producer/committer pipeline; sendfile/splice zero-copy for raw data and MSG_ZEROCOPY for prepared payloads; adaptive LZ4 → zstd(-1/1/3) driven by who waits on whom; chunk bitmaps for resume; fallocate + streaming writeback |
android/app/src/main/cpp/vortex.* |
Vortex tunnel (after VortexTunnel): [u32 len][u8 flag] framing, X25519 + pairing-key handshake, sequence nonces, optional plain mode |
android/app/src/main/cpp/aegis.* |
AEGIS-128L on ARMv8 AES / x86 AES-NI, IETF known-answer self-test at startup; XChaCha20-Poly1305 (Monocypher) fallback |
android/app/src/main/cpp/perf.* |
Big-core affinity, raised priority, ADPF performance hints |
android/app/src/main/cpp/bench.* |
Built-in device benchmark |
android/app/src/main/cpp/media.* |
Media shrinking with the bundled FFmpeg 8 (LGPL) and MediaCodec hardware encoders |
android/app/src/main/kotlin/ir/neovortex/wingdrop/ |
Wi-Fi Direct / local hotspot (2.4/5/6 GHz, WPA2/WPA3), DNS-SD discovery, MediaStore/SAF fds, QR scanner (CameraX + ZXing), HEIC, installer |
lib/ |
Flutter UI (BLoC), English + Persian |
- Control connection: 64-byte Hello, BLAKE2b-authenticated with the QR key, a trusted-device bond key, or the advertised radar key. Then the Vortex handshake (X25519 always; message encryption only in secure mode), then options (with sender identity and a stable transfer id) and the manifest.
READY(status, receiver caps, bond offered, receiver device id, chunk bitmap). The sender skips chunks the receiver already has, which is how resume works.- Data connections (one per stream): Hello authenticated with the session data key, then
FrameHeader(24 B) + payload. The payload is raw, LZ4 or zstd, and/or AEAD (AEGIS-128L or XChaCha20-Poly1305) with the header as associated data. - The receiver sends
DONEonly after every byte has been written.
Trust levels: a QR pairing or a bond is let in directly. The radar key needs the receiver's approval ("Accept" or "Accept and remember them"). A bond is derived from the X25519 session and stored by both phones.
Follow-up sessions: while media is still being shrunk, the ready files go first. Once the receiver accepts, both sides derive a follow-up key from the session (BLAKE2b "wdr-follow"); the shrunk files then come in a second session authenticated with it, with no second approval. Receivers keep these keys in memory for 30 minutes.
Resume: on failure the receiver keeps the partial files and the chunk bitmap, keyed by transfer id, for 24 hours.
flutter build apk --release --split-per-abi
libffmpeg.so in android/app/src/main/jniLibs is a prebuilt LGPL FFmpeg 8 build (avbuild), with headers in cpp/third_party/ffmpeg/include. Other vendored code: LZ4 (BSD), zstd 1.5.7 (BSD), Monocypher (BSD-2/CC0), Nunito and Vazirmatn fonts (OFL).