Delta Chat introduces real-time P2P networking with hole punching and forward-secret E2EE

Delta Chat has announced the release of Delta Chat 1.48 across all platforms, following nearly two years of collaboration with the Iroh team. This update introduces advanced Peer-to-Peer (P2P) networking capabilities, including hole punching and forward-secret end-to-end encryption.

The update enables Delta Chat to form private P2P gossip networks when users launch a webxdc app utilizing the new joinRealtimeChannel() API. Participation in a P2P network is initiated only when this specific API is used. Delta Chat sends an encrypted “system” chat message containing an Iroh Ticket to a group chat, allowing receiving devices to join the real-time channel and establish direct connections without delays from global distributed hash table lookups.

To facilitate direct P2P connections, two devices use an Iroh Relay typically hosted on chatmail servers, leveraging the existing e-mail federation. The Iroh relay server offers both STUN and TURN functionalities for peer discovery and direct connections.

Delta Chat employs ephemeral cryptographic identities for P2P messaging, generating a new identity each time the app is restarted. The networking layer utilizes QUIC, ensuring Forward Secrecy for secure communications.