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Version: 0.14

Private Multisig

Private multisig on Miden allows multiple parties to collectively control an account, requiring a configurable threshold of signatures (N-of-M) to execute transactions — all while keeping account state private.

The problem​

On public chains, multisig coordination is straightforward: every signer can read the same onchain state and build their next action on top of it. Safe-style multisigs work because the ledger is transparent.

In Miden's private account model, account state lives client-side. The chain stores only cryptographic commitments. This means:

  • Signers can't independently observe the latest state from the chain.
  • Proposals and signatures need an offchain coordination surface.
  • Without a shared state view, participants risk divergent state or stale approvals.

The Miden Guardian solves this by acting as the coordination server for multisig accounts — keeping signers synchronized, managing proposal workflows, and ensuring all parties work from the same canonical state.

How it works​

Miden multisigs can be fully private (code, signers, metadata, etc. are not visible). Guardian coordinates the workflow:

  1. Propose: A signer pushes a delta proposal (containing a TransactionSummary) to Guardian. Guardian validates the proposal against the current account state and the Miden network.
  2. Sign: Other authorized cosigners fetch the pending proposal from Guardian, verify the transaction details locally, and submit their signatures.
  3. Ready: Once enough signatures are collected (meeting the threshold), Guardian emits an acknowledgment.
  4. Execute: Any cosigner builds the final transaction using all signatures plus the Guardian acknowledgment, and submits it onchain.
  5. Sync: All participants fetch the latest canonical state from Guardian.

Learn more​

Under the hood

Core concepts

Transaction lifecycle, key architecture, and offline fallback.

miden-multisig-client

Rust SDK

Rust SDK for building multisig workflows.

@openzeppelin/miden-multisig-client

TypeScript SDK

TypeScript SDK for building multisig workflows.

Repositories​

RepositoryDescription
Miden GuardianGuardian server, client SDKs, and multisig client libraries
MultiSigMultiSig reference application (Next.js frontend + coordinator)