Mode 1 — Peer-to-Peer TC

In Mode 1, participants exchange threshold protocol messages directly. There’s no intermediary CA, no PKCS#11 adapter, no existing infrastructure to integrate with — just nodes running Confium and a transport between them.

When to choose Mode 1

  • You’re building a new distributed system from scratch.
  • Both sides of every signing session are online (or can complete sessions across hours via async messaging).
  • You want minimal moving parts — no adapter, no translation layer.
  • You don’t need to interoperate with an existing PKI consumer.

Typical Mode 1 deployments: MPC, distributed custody, BFT consensus, threshold-key backup, multi-stakeholder signing of any kind where the participants already have a channel.

What you need

  • A libconfium build on each participating node.
  • The threshold protocol crate matching your algorithm choice (FROST, CMP20, GG18, threshold ElGamal).
  • A transport — pick from confium-net-tcp, confium-net-quic, confium-net-ws, or supply your own via the confium-net abstraction.
  • A deployment manifest (TOML) describing signers, quorum policy, and algorithm allow-list.

Signing flow

  1. Setup: Each party generates a key share. The shares collectively form the threshold key but no single share reveals the secret.
  2. Session start: One party initiates a signing session with the coordinator, specifying the message, threshold, and participant list.
  3. Round 1, 2, …: Each party commits nonces and partial signatures. The coordinator aggregates inputs.
  4. Finalization: Once T parties have participated, the coordinator produces the final signature. The signature is indistinguishable from one produced by a single-key signer.
  5. Audit: The signing event is recorded in the transparency log.

Async vs synchronous sessions

Mode 1 sessions can be:

  • Synchronous — all parties online, session completes in seconds.
  • Asynchronous — parties join and submit over hours or days. The coordinator holds state until threshold is reached.

The async mode is what enables globally distributed signers. A director in Tokyo can submit their share during their workday; a director in New York submits theirs hours later; the coordinator combines them when quorum is reached.

See also