Security is a top concern when sharing files online. Every day, millions of sensitive documents — contracts, medical records, financial reports — are sent through services that store copies on their servers. WebRTC-based P2P transfer offers a fundamentally different security model.
WebRTC connections are encrypted by default using DTLS (Datagram Transport Layer Security). This means every byte of data that travels between the sender and receiver is encrypted before it leaves the browser. Even if someone intercepts the network traffic, they cannot read the file contents.
The encryption process works through a key exchange that happens when the connection is established. Each browser generates a unique encryption key pair, and they securely exchange public keys through the signaling server. After this initial handshake, all data flows through the encrypted P2P channel — the signaling server is no longer involved.
This is called end-to-end encryption (E2EE). Unlike services that encrypt data "in transit" but decrypt it on their servers, WebRTC encryption means only the sender’s and receiver’s browsers can read the data. No middleman — not even BigFileDrop — can access the file contents.
Another security advantage of P2P transfer is the absence of stored data. When you upload a file to a cloud service, that file exists on their servers until it’s deleted (and sometimes even after). With BigFileDrop, files exist only in the RAM of the two connected browsers during transfer. Once the tab is closed, the data is gone.
BigFileDrop also uses ICE (Interactive Connectivity Establishment) to find the best connection path. When possible, it creates a direct P2P connection. When firewalls or restrictive NAT prevent direct connections, it falls back to a TURN relay server — but even then, the data remains encrypted end-to-end. The relay server cannot read the contents.
For users who need to share sensitive files — legal documents, personal photos, business data — this security model provides peace of mind. No server logs, no stored copies, no third-party access. Just a secure, encrypted pipe between two browsers.