flipflop

croc is a command-line tool for transferring files and directories between computers using a short code phrase rather than manually configuring SSH servers, firewalls, keys, or IP addresses. It uses peer-to-peer connections with relay fallback and end-to-end encryption based on PAKE, supports resumable and multiple transfers, and does not require a local server or port forwarding. The tool supports Windows, Linux, macOS, and browser clients, can use proxies such as Tor, and allows custom relay servers.

OpenFlux is a network-stack research tool that creates a TCP tunnel with pluggable transports. A client exposes a SOCKS5 proxy, sends TCP packets through a selected transport to an exit node, and the exit node decapsulates and forwards them to the destination. The repository provides transports using Yandex Docs cursor messages and MAX Messenger WebRTC DataChannel; custom transports can implement its Transport interface. It includes desktop, Android, and iOS build paths and is distributed under the GNU General Public License v3.0 or later. The README describes the MAX transport as experimental and warns that using external infrastructure or accounts may lead to account restrictions.

Decimen Optical Transfer is an open-source browser-based file-transfer tool by Evan Crawley that sends files between devices using only a screen and a camera, without a network connection, pairing, permissions beyond camera access, or a dedicated app. The sender displays an endless stream of animated QR codes; the receiver collects fountain-coded frames in any order and uses Luby transform decoding to reconstruct the payload, so dropped frames affect transfer time rather than correctness. Transfers preserve filenames and media types, accept pasted text, support files up to 64 MB, and verify completed payloads with SHA-256. The web app works offline after its first visit and can be installed on iOS and Android home screens. QR streams can also be exported as APNG or PNG sequences for playback from a file, page, or video. Transmissions are not encrypted: data is readable by any camera pointed at the sending screen. The project is licensed under AGPL-3.0-or-later as of v0.4.0; releases through v0.3.0 remain available under the MIT license.

BlueFerry is experimental Linux software that connects a paired iPhone to a Linux desktop over Bluetooth, without a Mac relay, Apple login, cloud service, or subscription. It provides native GTK, KDE/Kirigami, Quickshell, and terminal clients for reading and sending SMS, RCS, and iMessage, starting conversations, syncing contacts, marking messages read, and optionally mirroring other iPhone notifications. Local message history can be encrypted with GNOME Keyring or KDE Wallet. It only receives messages observed while connected and does not download an iCloud Messages archive. Attachments, reactions, typing indicators, FaceTime, calls, and complete sent-message history are unsupported; group replies are disabled or require confirmation when Bluetooth does not provide enough participant information. The project distributes native packages for several Linux distributions and warns that changes to iPhone Bluetooth behavior could affect compatibility.

QRFerry transfers files between two devices as a live animated QR stream. The sender and receiver run in the browser, and the file is not uploaded to an application server. The protocol optionally compresses the file with Brotli or gzip, then divides the payload into QR frames containing binary headers, RaptorQ source or repair symbols, and CRC-32 checksums. Fountain coding lets the receiver reconstruct the file from enough unique symbols while tolerating blurred, missing, out-of-order, or mid-stream frames. The receiver verifies frame, compressed-payload, RaptorQ-object, and original-file checksums before saving the file. QR rendering, scanning, and RaptorQ encoding and decoding use WebAssembly implementations of fast_qr, ZXing-C++, and an RFC 6330 RaptorQ implementation.