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Optical
Data over camera
One screen displays encoded frames; the other camera captures them.
Taftan renders the message as a grid of QR-style tiles on the sender's screen. The receiving device holds its camera facing the screen and rebuilds the message frame by frame. It is similar in concept to scanning a QR code on a product label, but uses a full grid of tiles to handle larger payloads. No additional configuration is needed on either device.
Strong points
- Handles larger payloads than the acoustic channel. Works for documents, photos and recovery codes.
- Completely silent.
- Works across a counter, window or glass partition where handing over the device is not possible.
Trade-offs
- Requires a clear line of sight. The camera must face the screen directly.
- Strong reflections on the screen surface can reduce scanning reliability.
When to use
Transferring data across a counter or window. Sharing a document when you cannot hand over the device. Sending a file too large for the acoustic channel.
Get started
Two devices. One shared password. No intermediary.
Install Taftan on both devices, agree on the password through a separate channel beforehand, and run a quick test transfer using whichever channel fits your situation.