What is File Sender?
File Sender is a portable desktop app for sending files directly to any party.
What is different about File Sender?
No servers are involved. The files are transferred directly from sender to recipient.
Do I need an account or an E-mail address?
No account or E-mail is required. No registration required. Download File Sender and send files immediately.
Is there a size limit for the transfer?
There is no file size limit when using the File Sender desktop app.
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Will the files be stored in a cloud?
Absolutely not. With the File Sender desktop app, files are sent directly from sender to recipient - no cloud relay or intermediate storage of any kind. The app is self-contained for both sending and receiving files using direct Person-to-Person (P2P) connectivity.
How does direct file transfer work?
An end-to-end encrypted channel is created between the sender's and recipient's apps. Once created, all files are transferred through this channel. The files are never stored on any servers when using the desktop File Sender app.
How will I know that my recipient downloaded the file(s)?
As a sender, you will be alerted by the app when the recipient completes the download. After that, no additional downloads will be possible. This is by design and provides extra security - a single download per download invitation.
Would it be faster to use OneDrive, Google Drive, or iCloud Drive?
Direct transfers between parties are faster since they can start immediately, without a separate upload and download process. As soon as the sender selects files to be transmitted, the recipient can download them immediately. An upload is a download.
More technical details
How are files transferred without a central service?
File Sender uses a Kademlia Distributed Hash Table (DHT) to connect sender and recipient. Unlike WebRTC, connections are established through a distributed peer-to-peer signaling system. Direct peer-to-peer connectivity is established between the sender's and recipient's apps via Hyperswarm, a stack of networking modules for finding peers and creating reliable connections between them.
How is direct connectivity established?
First, the sender's app generates internally a new download invitation comprised of a unique Download Code and a PIN Code. The sender's app joins the peer-to-peer network and advertises the Download Code (but not the PIN Code). This allows someone with knowledge of the Download Code to send a 'connect' invitation to the sender.
Next, the recipient's app looks up the sender on the peer-to-peer network via the Download Code. Once connected, the recipient's app provides the PIN code to verify the invitation. If the invitation is verified, the sender's app presents to the recipient a list of files available for a download.
Direct connectivity is afforded by an end-to-end encrypted, secure channel based on the Noise Protocol Framework. Once the download is complete, the invitation information is discarded, and no additional downloads are possible.
Would a recipient be able to see my IP address?
Yes, a technically inclined recipient would be able to determine the sender's IP address (but not if the sender uses a VPN). This is no different than the sender revealing his or her IP address to Microsoft, Google, or a visited web site, except that there is typically more trust between a sender and recipient who share files as compared to one's trust to an unrelated corporation or web site.
As with any internet activity, the privacy of your IP address is best protected with a VPN service.
