Peer-to-peer file-sharing protocols: which one fits your task?

Peer-to-peer (P2P) file sharing is a design, not one protocol. Use BitTorrent to distribute files through shared pieces, Syncthing's Block Exchange Protocol (BEP) to keep folders in sync, or Tella Nearby Sharing for a file handoff over local Wi-Fi without internet access.

In short:

• File distribution. BitTorrent lets downloaders share the work of transferring the same files.
• Folder synchronization. Syncthing's BEP requests missing or outdated blocks between devices.
• Nearby handoff. Tella sends files over local Wi-Fi after the receiver accepts the request.

Choose a protocol for the kind of sharing you need

The protocol details here refer to BitTorrent's base specification, Syncthing's v1.30.0 documentation and Tella Nearby Sharing protocol version 2. These versioned documents don't establish what every currently installed application supports. Transport Layer Security (TLS) is the connection layer used for encryption and certificate-based authentication in BEP and Tella.

Compare the same criteria across these three sharing workflows.

BitTorrent fits distribution because concurrent downloaders upload pieces to each other. BEP fits continued synchronization because devices request blocks needed to match the shared folder model. Choose Tella's documented local workflow when you need to hand off files nearby, not keep folders continuously aligned.

Keep your existing protocol when its workflow and access controls still fit. Direct transfer alone isn't a reason to replace ongoing synchronization or multi-peer distribution.

How devices find each other

BitTorrent's base specification uses a tracker, a service that returns connection details for other peers. Those details include a self-selected peer identifier, an Internet Protocol (IP) address or Domain Name System (DNS) name, and a port. The tracker helps devices find connection endpoints, but a self-selected identifier doesn't authenticate a person.

BEP defines device address lists used to connect to other devices. Those addresses are separate from the certificates used for authentication. An address list alone doesn't describe how local or global discovery finds those addresses.

Tella's receiver displays a QR code containing its local IP address, port, certificate hash, connection personal identification number (PIN) and protocol version. Manual connection supplies local connection details when scanning isn't available. This workflow uses local Wi-Fi without needing an internet connection.

P2P doesn't mean every design works without supporting servers. Finding an address also doesn't prove that the device at that address is the one you intended to contact.

How files move and get checked

A hash is a value used to compare content with an expected value. BitTorrent requests portions of pieces using a piece index and byte offsets. After downloading a complete piece, a peer checks its hash before announcing that it has the piece to other peers.

BEP exchanges folder models and requests missing or outdated blocks from other devices. Its file metadata lists the size and hash of each block. This block-based exchange supports continued synchronization as folder contents change.

Tella sends file metadata first, including a whole-file SHA-256 hash. The receiver can accept or reject the request before the sender uploads file data. The hash field alone doesn't establish a mandatory receiver-side check after upload. Even a matching hash doesn't prove a file is harmless.

What to check before sharing private files

Encryption, peer authentication and permission to receive files are different controls. BitTorrent's base specification describes distribution, but it doesn't establish private-recipient authorization or encrypted transfers. Its random peer identifier isn't proof of a person's identity. Check your client's documented controls instead of assuming every BitTorrent implementation has the same privacy features.

BEP requires TLS 1.3 or later with certificate-based authentication. Syncthing's folder-type documentation distinguishes ordinary send-and-receive folders from send-only and receive-only folders. Send-only mode shares local changes without applying incoming updates. Receive-only mode applies changes from other devices without distributing its own local changes; it can still relay received updates. Check the folder mode on each device rather than assuming it makes the connection itself one-way. For private folders, confirm both the participating devices and the intended direction of changes.

Tella uses mutual TLS (mTLS), meaning each device checks the other's certificate. QR scanning supplies certificate values for verification, while manual connection requires comparing the values shown on both devices. If they don't match, stop instead of accepting the mismatch. Receiver acceptance of the file request is a separate control from authenticating the connection.

Tella protocol version 2 is incompatible with version 1 because version 2 requires mutual TLS. Check protocol compatibility before attempting a nearby transfer. Encryption doesn't prevent an authorized recipient from saving or redistributing your file.

Where doxx.net fits. doxx.net offers direct device-to-device connections and full, unmodified file transfer between devices on its private network. If that fits your task, create an account, download the app and connect a device.