)
A layered, end-to-end encrypted group-messaging protocol family built on top of MLS (RFC 9420). One base protocol — GBP — provides framed, replay-protected, AEAD-encrypted delivery; three sub-protocols — GTP, GAP, GSP — provide message semantics for text, audio and signalling, the way TCP and UDP build on top of IP.
┌── application ──────────────────────────────────────────────────────┐
│ GTP · GAP · GSP (TCP / UDP / SCTP-like) │
├─────────────────────────────────────────────────────────────────────┤
│ GBP (the IP-like base) │
│ - frame codec - AEAD - replay window - FSM - control plane │
├─────────────────────────────────────────────────────────────────────┤
│ MLS (RFC 9420) (group key agreement, exporter) │
└─────────────────────────────────────────────────────────────────────┘
The same protocol family is published from one source tree to every major
package manager. Each binding ships pre-built native binaries for win-x64,
win-arm64, linux-x64, linux-arm64, osx-x64 and osx-arm64.
| Language | Package | Source | README | Examples |
|---|---|---|---|---|
| Rust | gbp-stack |
crates/gbp/stack |
README | gtp_chat · gap_audio · gsp_signals |
| .NET | GBPStack |
csharp/GBPStack |
README | GtpChat · GapAudio · GspSignals |
| Python | gbp-stack |
python |
README | gtp_chat · gap_audio · gsp_signals |
| Node.js | @voluntas-progressus/gbp-stack |
js |
README | gtpChat · gapAudio · gspSignals |
| Browser (WASM) | @voluntas-progressus/gbp-stack-wasm |
crates/gbp/wasm |
README | gtpChat · gtpChat (html) |
The reference implementation is a Rust workspace. The umbrella crate
gbp-stack re-exports every layer; smaller consumers
can depend on individual crates directly.
| Crate | Purpose |
|---|---|
gbp-core |
Shared type vocabulary (StreamType, flags, FSMs, error codes) |
gbp-protocol |
Base GBP layer: GbpFrame, control plane, ErrorObject |
gtp-protocol |
Group Text Protocol (text + attachments + history/watermark) |
gap-protocol |
Group Audio Protocol (Opus + key-overlap buffer + jitter) |
gsp-protocol |
Group Signaling Protocol (signals + per-signal validation + roles + capabilities) |
gbp-mls |
MLS (RFC 9420) integration via openmls |
gbp-transport |
Length-prefixed TCP adapter + async QUIC transport (quinn) |
gbp-node |
GBP-layer group node (FSM, replay, control plane, coordinator handover, timer engine, tie-break) |
gbp-sframe |
SFrame (draft-ietf-sframe-enc) E2EE for GAP audio streams |
gbp-proto |
Protobuf schemas for GBP/GTP/GAP/GSP (via prost, no protoc) |
gbp-flat |
FlatBuffers schemas for GBP/GTP/GAP/GSP (via planus, no flatc) |
gbp-stack |
Top-level facade re-exporting every layer |
gbp-stack-ffi |
C ABI / cdylib for non-Rust consumers |
gbp-cli |
Reference CLI (`gbp-node listen |
Every sub-protocol (GTP, GAP, GSP) can encode its payload as CBOR,
Protobuf, or FlatBuffers. The codec is negotiated per-frame via
the pf field of the enclosing GBP frame. The default (pf=0, CBOR) is
omitted from the wire for backward compatibility.
PayloadCodec::Cbor (0) — default; pf field omitted when 0
PayloadCodec::Protobuf (1) — via gbp-proto / prost
PayloadCodec::FlatBuffers (2) — via gbp-flat / planus
Callers pass codec to every send / accept call; the chosen codec is
echoed back in the payload_received event so the receiver can decode correctly.
See docs/ for the protocol specifications (English in
docs/en/, Russian in docs/ru/).
Licensed under Apache License, Version 2.0.