Participant Seed Contract v1

Based on:

• doc/project/40-proposals/007-pod-identity-and-tenancy-model.md
• doc/project/40-proposals/017-organization-subjects-and-org-did-key.md
• doc/project/20-memos/console-participant-identity-create-and-import.md

This memo freezes the local recovery-seed contract used for explicit participant identity creation and import in Orbiplex Node MVP.

Contract

• Contract name: orbiplex-participant-seed-v1
• Wordlist: BIP39 English
• Word count: 12 words for MVP, with 24 words accepted by the derivation path
• Seed KDF: BIP39 standard PBKDF2-SHA512, 2048 iterations, empty passphrase
• Derivation: SLIP-0010 Ed25519
• Path: m/44'/2268'/0'
• Key algorithm: Ed25519
• Accountable id encoding:
• public key -> multicodec 0xed01
• multibase base58btc
• final form participant:did:key:z...

Scope

This contract applies only to participant recovery material.

It does not change:

• node-identity.v1
• the automatic creation of one local node-id
• org identity generation in MVP

node-identity.v1 remains infrastructure identity for the node as a network actor. Participant identity remains an explicit operator action.

Create flow

Create Participant means:

1. generate a fresh BIP39 English mnemonic,
2. derive a deterministic Ed25519 participant signing key via orbiplex-participant-seed-v1,
3. derive canonical participant:did:key:...,
4. persist the signing key locally,
5. optionally persist the recovery phrase in local secret storage,
6. show the mnemonic phrase to the operator exactly once.

The mnemonic phrase is never appended to the fact stream.

Import flow

Import Participant means:

1. accept a mnemonic phrase from the operator,
2. derive the participant signing key through the same contract,
3. derive canonical participant:did:key:...,
4. persist the local signing key binding,
5. optionally persist the recovery phrase in local secret storage.

Because create and import share the same contract, one mnemonic phrase always maps to one stable participant-id.

Local secret storage

If the operator explicitly asks the node to keep the recovery phrase, it is stored in local secret storage outside the append-only fact streams.

The local record is:

• mutable,
• deleteable,
• operator-local,
• and never replayed as a public fact.

The presence of stored recovery material may be surfaced through an operator read model such as recovery_seed_stored = true.

Export

Existing participants may be exported only through an explicit recovery export operation.

Preferred export:

• stored mnemonic phrase, if available

Fallback export:

• private key material, if mnemonic was not stored locally

This operation is intentionally named as recovery export rather than generic identity export, because it yields high-sensitivity recovery material.