Three approaches to different boundaries
Threshold MPC coordinates participants to produce a signature using distributed secret shares. Multisig requires multiple signatures, with the approval rule enforced by a chain protocol or a wallet contract. A trusted execution environment (TEE) isolates sensitive computation inside a hardware-backed execution boundary.
These approaches can be combined. A multisig owner can use distributed signing, and a signing participant can run inside an enclave. The useful question is which boundary protects which part of your operation.
MPC: inspect participant independence
For threshold signing, evaluate the protocol, threshold, participant operators, communication assumptions, and recovery design. Distributing shares across machines does not necessarily distribute administrative control. Ask how the system handles unavailable or malicious participants and how it proves a signer rotation.
Hybrid-Chain describes a first-valid seven-of-thirteen architecture across three cloud providers, with a separate all-thirteen admission gate. That is its stated architecture; consult the product page for activation restrictions before assuming a network is available.
Multisig: inspect the on-chain rule
A multisig wallet verifies approvals from multiple keys. In a smart-contract implementation, the contract expresses the execution rule. Assess owners, threshold changes, modules, upgrade paths, supported networks, and transaction costs. The wallet’s authorization logic is only as strong as the paths that can alter or bypass it.
TEE: inspect the execution boundary
Coinbase documents CDP wallet key operations inside AWS Nitro Enclaves, with keys kept from leaving that boundary in plaintext. Evaluate the enclave design alongside request authentication, credential rotation, policy enforcement, and recovery. Hardware isolation and distributed signing make different assumptions; neither label alone establishes suitability.
Choose using the same acceptance tests
Require each design to explain unauthorized requests, credential loss, participant or provider outages, policy changes, and transaction replay. Compare the evidence you can obtain for each outcome. A custody label or architecture acronym cannot answer those operational questions on its own.