Android receiver privacy policy

Developer and scope

DisplayDuo provides the DisplayDuo Android receiver (com.displayduo.receiver). For privacy questions or requests, contact [email protected]. This policy describes the Android receiver. The Mac app and website have their own privacy policy.

The receiver connects directly to your Mac over Wi-Fi or a USB accessory connection. Its streaming and diagnostic code does not send data to a developer server and includes no advertising, analytics, or account sign-in service. Opening this policy in a browser makes a separate website request; sending support email uses your email provider and sends the information you choose to include to DisplayDuo.

Device information and screen content

At connection setup, the receiver sends your Mac the device model, usable panel dimensions, refresh rate, pixel density and physical size, phone/tablet classification and orientation, transport type, and hardware decoder capabilities. Decoder information includes names, formats, profiles, levels, size and frame-rate limits, and low-latency support. This lets the Mac select a compatible display stream. The receiver also stores a copy of the setup information in local session diagnostics.

Screen content travels from your Mac to the Android device for display. The receiver processes video in memory and does not save a screen recording or screenshots. Frame timing and size measurements, rather than video content, are saved in local diagnostics. Data received by the Mac is handled by the Mac app under its own policy.

Pen, touch, and connection statistics

To control the Mac, the receiver sends pen and supported touch actions, button state, normalized coordinates, pressure, scroll direction and distance, and event timestamps to the connected Mac. Individual input payloads are used during the connection, not written to the receiver’s diagnostic files; those files contain input counts and dropped/coalesced-event counts.

The receiver sends rendered/dropped frame counts, average decoding time, clock offset, round-trip time, and received-byte counts to the Mac. Clock synchronization also exchanges timestamps. These measurements support connection operation and troubleshooting. Timing, performance counters, and connection history are also retained in local session files.

Discovery and connection diagnosis

Local network discovery looks for DisplayDuo Macs and resolves their service names, addresses, and ports. Discovery requests are visible on the local network. If multicast discovery finds nothing after four seconds, the foreground picker can check addresses on the selected Wi-Fi IPv4 subnet (/24 through /30), using at most 16 simultaneous, short TCP connections to port 47800 with no payload. Results are unverified candidates until TLS and application setup succeed; scan results alone are not saved. Reconnection and the Diagnose button can try the remembered Mac’s addresses using TCP connections without sending a display handshake during the probe.

Diagnosis inspects Wi-Fi status and checks the local router at TCP ports 80, 443, and 53. Automatic diagnosis after certain connection failures may also use the platform’s router reachability check. These probes check for a response, not router web content, and do not upload a report. The recipients are the discovered or remembered Mac endpoint and the local router; no public diagnostic service is used.

The Diagnose panel keeps its results in memory and writes a summary of statuses and counts to Android system logs. Automatic session failure diagnostics can retain device IP addresses and subnet prefixes, the Mac host/address and port, router address, connection type, retry counts, reachability results, timestamps, and error details in local session files. Release session records redact addresses, USB metadata, and raw error details. Debug builds may retain those details.

Remembered Mac and local records

To reconnect, the receiver saves the selected Mac’s service name, address and port, and connection origin in private app preferences. When the Mac supplies connection details over USB, it saves the Mac name, IPv4 address list, port, and saved/updated time. A later discovery can refresh those details. The record also stores a certificate SHA-256 fingerprint and whether it was verified over USB or first trusted over Wi-Fi. Metadata updates and picker selections preserve that pin; USB verification can replace it, and Forget this Mac removes it. This record is updated as you use a Mac; it has no automatic expiry and is not sent to a developer server.

Session diagnostics are saved automatically when a session ends, including in release versions. They contain setup and decoder information, frame IDs/timestamps/sizes, performance histories, connection and error events, rotation/reconnection measurements, and USB accessory metadata when available (manufacturer, model, version, description, and serial). The receiver does not automatically upload these files.

The files are in the app-specific external files directory. The latest android_session.json and android_frames.csv are overwritten by later dumps. Phones also retain separate session folders; rotation_restarts.json stores rotation measurements. There is no age-based cleanup of session archives. Release Android system logs omit addresses, names, serials and raw exception details; debug builds may retain them; their retention and access are controlled by Android, not a fixed app retention period.

Transport security and your choices

Wi-Fi connections are encrypted (TLS 1.3); a direct USB cable connection is not encrypted. The receiver remembers the Mac certificate fingerprint. A first Wi-Fi connection uses trust on first use and does not protect against an active attacker on that first connection. Connect once over USB to verify or replace the remembered fingerprint through the physical connection. Discovery results and remembered names or addresses do not authenticate a Mac. USB relies on physical trust; server authentication does not authorize the Android device.

Disconnect or close the receiver to stop the active session. Clear the app’s storage in Android settings or uninstall it to remove its remembered-Mac preferences and app-specific diagnostic files. Android backup is disabled. Copies you export or send to support, records on your Mac, and Android system logs are not removed by clearing the receiver’s storage. This receiver has no automatic diagnostic-upload or report-sharing function.

If you email support, DisplayDuo receives your email address and message, including any files you attach. Send only the information you want to share and contact [email protected] with deletion requests. We will update this page when the receiver’s data handling changes.