How to Transfer Files via Light with Decimen Optical Transfer

Decimen Optical Transfer is an innovative method for transferring files between devices using light, without the need for network connections, Bluetooth, cables, or cloud services. This open-source, browser-based tool converts a file into a sequence of animated QR codes displayed on a screen, which another device can capture with its camera to reconstruct the original file.

This solution is particularly useful in situations where establishing a network connection is inconvenient, undesirable, or impossible. Decimen is ideal for technical users who need to transfer files quickly and securely without relying on traditional network infrastructures.

The transfer occurs through a series of animated QR codes that do not require a specific order for file reconstruction, thanks to the use of Luby Transform fountain coding. This method allows transferring files up to 64 MB and text up to 4 MB, maintaining data integrity and security through SHA-256 integrity checking.

Prerequisites

• Hardware: Two devices with a screen and camera (e.g., smartphone, tablet, laptop)
• Software: Modern web browser (e.g., Chrome, Firefox, Safari, Edge) on both devices
• Internet Connection: Only for the first access to the web app (can work offline afterward)

Procedure: File Transfer with Decimen Optical Transfer

Following this guide, you will transfer a file between two devices using Decimen Optical Transfer, without needing a network connection, account, or native applications.

• Open the web app Decimen on both devices.
• On the sending device, select the "Send" option.
• Choose the file you want to transfer.
• Grant camera access.
• Aim the receiving device's camera at the sending device's screen.
• Ensure the QR code fills the camera frame as much as possible.
• Increase the sending device's screen brightness to improve signal quality.
• Wait for the transfer to complete and for the SHA-256 integrity check to succeed.
• Once the transfer is complete, the reconstructed file will be available for preview and saving.

Verification and Troubleshooting

Follow these steps to test the functionality of Decimen and resolve any issues.

Functionality Test

• Preparation: Ensure both devices have access to a web browser and are capable of running JavaScript.
• Role Selection: On the sending device, select "Send" and choose a file. On the receiving device, select "Receive" and grant camera access.
• Transfer: Aim the receiving device's camera at the sending device's screen. Verify that the stream of animated QR codes is visible and that the camera captures it correctly.

Troubleshooting

• QR code display issues: If the QR codes are not visible or not captured correctly, increase the sending device's screen brightness and ensure the QR code fills the camera frame as much as possible.
• Slow or interrupted transfer: If the transfer is slow or interrupted, ensure there are no obstacles between the two devices and that the camera is well positioned to capture the QR code stream.
• File integrity error: If the SHA-256 integrity check fails, repeat the transfer ensuring the camera captures all necessary frames. Remember that the order of the frames is not important, but about 115% of the minimum required frames are needed.
• Compatibility issues: If the app does not work correctly, ensure you are using an updated browser and that JavaScript is enabled.

Security Considerations

Remember that Decimen does not encrypt the transferred content. If you need to transfer sensitive files, consider encrypting them separately before using Decimen.

At the end of this guide, you will have learned how to use Decimen Optical Transfer to transfer files between devices using light, without needing network connections, accounts, or native applications. You are now ready to put this innovative solution into practice.

Educational Summary

• Decimen is an open-source tool that transforms files into streams of animated QR codes.
• Transfer occurs through the camera of one device reading the screen of another.
• It does not require network connections, accounts, or native applications.
• Supports files up to 64 MB and text up to 4 MB.
• Uses Luby Transform fountain coding for flexible data reconstruction.
• Works offline and can be installed as a Progressive Web App.
• Does not encrypt transferred data, so it is advisable to encrypt sensitive files before transfer.

Call to Action

Try Decimen Optical Transfer to transfer files simply and securely. Open the web app on both devices, select "Send" on one and "Receive" on the other, and start transferring your files via light.

For more details, consult the official documentation on GitHub.