Key takeaways
- Multisig is an on-chain rule: M of N complete keys must sign, and the network checks the signatures. MPC is an off-chain method: shares of one key cooperate to produce one standard signature.
- A multisig approval structure is generally visible on-chain once funds are spent. An MPC approval structure is not visible on-chain; it can only be verified from the provider's documents and audit evidence.
- Multisig depends on what each blockchain supports. MPC produces a standard signature, but support for a given network still depends on the signature scheme and the provider's implementation.
- Neither model removes the risks around the people, the approval policy, the backups and the legal structure. Those need their own evidence.
- Hex Trust states that it keeps private keys in HSMs validated to FIPS 140-3 Level 3. The pages read for this guide do not describe an MPC or multisig layer, so ask which wallets use which model.
How multisig works
Multisig, short for multi-signature, requires a set number of independent keys to approve a transaction, and the blockchain itself checks that rule. A common set-up is “2 of 3”: three keys exist, and any two must sign. Bitcoin Improvement Proposal 11, written in 2011, proposed M-of-N transactions as a standard transaction type on Bitcoin, and several other networks support similar rules, either in the protocol or in smart contracts.
Each key in a multisig is a complete private key held by one signer, often in separate hardware or by separate people. No single signer can move the funds, and the approval rule cannot be skipped, because a transaction missing signatures is simply rejected by the network.
Two consequences follow. First, the structure is transparent: for many networks, anyone can see on-chain how many signatures a spend needed. Second, the rule belongs to that blockchain. A multisig on one network cannot simply be carried to another, and some networks support it poorly or only through smart contracts, which carry their own code risk.
How MPC works
MPC lets several parties compute a result together without any of them revealing their own input. In custody, the result is a digital signature and the inputs are key shares. The shares are created so that a complete private key never exists in one place, and a threshold of the parties must take part to sign. The US National Institute of Standards and Technology (NIST) describes this field as threshold cryptography and runs a project on it. The guide to what MPC is covers the mechanics in more detail.
The signature that results is a standard one. To the blockchain, the transaction looks as if a single ordinary key had signed it. The approval rule, say two of three parties, is enforced by the protocol the parties run among themselves, not by the network.
That is the main practical contrast. Because the network sees only a normal signature, MPC does not depend on a chain's built-in multisig feature, and the set of share holders can in principle change without changing the wallet address. In return, nobody outside the provider can confirm from the chain that the approval rule was applied.
Side-by-side comparison
The table sets the two models against the points an institution usually weighs. It describes the general design of each model, not any one provider's product.
| Point | Multisig | MPC |
|---|---|---|
| Where the rule is enforced | On the blockchain, by script or smart contract | Off-chain, by the signing protocol between the parties |
| What exists as a key | Several complete private keys | Shares of one key; no complete key is assembled |
| What the chain sees | Several signatures, or a contract call | One ordinary signature |
| Can an outsider check the approval rule? | Often yes, on-chain | No; only through the provider's documents and audits |
| Network support | Depends on each chain's features | Depends on the signature scheme and the implementation |
| Changing the signers | Usually a new address and a transfer of funds, unless a contract allows rotation | Possible to refresh or reassign shares without a new address, depending on the design |
| Main technical risk | Key loss or theft at each signer; contract bugs on smart-contract wallets | Flaws in the protocol or its implementation; compromise of enough shares |
| Standards and certification | Rule is a protocol feature; signer hardware can be validated | No single settled certification; NIST threshold work is still under way |
Prepared for this guide from the sources listed below. Last reviewed .
Trade-offs in practice
Transparency against portability
Multisig lets a counterparty or auditor see for themselves that a wallet needs several signatures, which is a real strength when an outsider must be satisfied without trusting the custodian's word. MPC gives up that visibility and gains one signing method across many networks. Which matters more depends on whether your reviewers need on-chain proof or broad asset coverage.
Maturity and complexity
Multisig rules are simple and have been used on Bitcoin for many years. MPC signing protocols are more intricate, so the quality of the implementation matters more and a reviewer should look for independent testing of the exact library in use. NIST's threshold cryptography project and its call for threshold schemes (NIST IR 8214C) show that standardisation is still in progress, so do not assume that one certificate covers all MPC products.
Operations and recovery
With multisig, replacing a lost or compromised signer often means moving funds to a new address. With MPC, shares can often be refreshed without moving funds, but recovery then depends on the provider's procedures, which you cannot inspect on-chain. In both models, ask how backups are stored and when recovery was last tested.
Fees and performance
On-chain multisig can cost more in fees on some networks because several signatures or a contract call are recorded. MPC records one signature but adds communication between the parties at signing time. Both effects vary by network and design, so test with your own volumes.
Where the whole key is held in tamper-resistant hardware instead, the trade-offs differ again; they are set out in MPC vs HSM vs multisig custody compared and the shorter guide to what a hardware security module is.
What neither model removes
A key model protects keys; it does not decide who owns the assets if a firm fails or who may approve a payment. Four risks sit outside the choice between MPC and multisig:
- Collusion. If enough signers or share holders act together, either model can be made to sign. Dubai's Custody Services Rulebook, as summarised in our custody due diligence checklist, expects the risk of collusion between signatories to be assessed.
- Policy and people. One administrator who can change the approval policy and sign defeats a quorum in either model.
- Legal structure. Who holds title and what happens in an insolvency is a question for the custody terms, covered in bankruptcy-remoteness for custodied assets and segregation of client assets.
- Control. Who holds the keys at all is a separate decision, compared in custody vs self-custody for institutions.
How Hex Trust describes its key storage
The live Hex Trust trust centre states that private keys are kept in HSMs validated to FIPS 140-3 Level 3, and names the vendor as Securosys Primus. The pages read for this guide do not state that Hex Trust uses MPC or on-chain multisig, and this guide does not claim that it does.
Ask which wallet tiers use which model and request the evidence. Hex Trust MENA FZE is licensed by VARA for Custody Services (VL/23/08/002); the licence covers custody only, and services such as wealth management, token wrapping and lending or staking of digital payment tokens are not offered under it. See the Hex Trust entities and leadership.
Questions to ask a custodian
- Which model protects my wallets: multisig, MPC, HSM or a mix, and does it differ by wallet tier or network?
- For multisig: how many signers, who holds each key and in what hardware, and can I see the structure on-chain?
- For MPC: which protocol and library, who audited that exact implementation, and where is each share held?
- How many people can approve a withdrawal, and can any one person change the policy?
- How are backups protected, and when was recovery last tested?
- What does the contract say about who holds title to the assets if the custodian fails?
These sit inside a wider review; the eight-area due-diligence checklist puts them next to licences, assurance reports and insurance, and the FAQ answers short questions about Hex Trust itself. A definition of the custodian's role is in what a digital asset custodian is.
FAQ
Is MPC the same as multisig?
No. Multisig is a rule enforced by the blockchain: several complete keys each sign, and the chain checks the signatures. MPC is a cryptographic method used off-chain: several parties each hold a share of one key and jointly produce one ordinary signature. The chain cannot tell that MPC was used.
Which is more secure, MPC or multisig?
Neither is more secure in every case. Multisig is simple and its rule is checked by the network itself, while MPC adds protocol complexity but keeps no complete key anywhere. Security depends on the implementation, on who holds each key or share, on the approval policy and on how recovery is handled.
Does MPC work on every blockchain?
MPC produces a standard signature, so it is not tied to a chain's own multisig feature. Whether it can sign for a given network still depends on the signature scheme that network uses and on what the provider has implemented. Ask a custodian for its list of supported networks and schemes.
Can a custodian use MPC and multisig together?
Yes. Some designs put MPC inside each signer of a multisig, or use multisig for some wallets and another model for others. Each layer adds protection and adds parts that can fail, so ask which model protects which wallets and what evidence exists for each.
Is MPC or multisig better for an institution?
There is no general answer. Multisig suits cases where an on-chain, publicly checkable rule matters. MPC suits cases that need one signing method across many networks or changes of signers without moving funds. Judge a custodian on the evidence behind its model, not on the label. This is not advice.
Sources
Standards and rulebook pages relied on for this guide, with the date each was last opened.
- Bitcoin Improvement Proposals, BIP 11: M-of-N Standard Transactions, opened 12 October 2026.
- National Institute of Standards and Technology, Multi-Party Threshold Cryptography, opened 12 October 2026.
- National Institute of Standards and Technology, NIST Threshold Call (NIST IR 8214C), opened 12 October 2026.
- Virtual Assets Regulatory Authority, Custody Services Rulebook, version effective from 19 June 2025, opened 12 October 2026.
Statements about Hex Trust come from its live website trust centre, read on 6 October 2026. The full text of the NIST documents and of BIP 11 was not re-read for this article beyond the points stated; the comparison table is a general description, not drawn from one source. Check the sources before relying on them.
This guide is for information only and is not investment advice, legal advice or tax advice. It does not recommend any custodian, key model or digital asset. Digital assets are volatile, and the risk disclosure for digital asset services sets out the main risks.
Ask how your keys would be protected
Ask institutional sales which key model protects each wallet tier, and request the documents that show it.
Risk warning. Not financial advice. Crypto is highly volatile and may drop in value significantly. You may lose the amounts you invest and your investments do not benefit from any form of financial protection.