---
title: "Who Controls Your Crypto? Multisig, MPC & Custody Risks"
description: "Who can really move your crypto? Understand multisig, MPC, custody models, key governance, recovery and the hidden legal risks of digital asset custody."
url: https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody
---

Digital Assets & Finance · 2 November 2026· 9 min read

# Who Controls Your Crypto?

Multisig, MPC and the Hidden Risks of Digital Asset Custody

By [Dr. Jovian Tan](https://joviantan.com/about) ·Published 2 November 2026

![Illustration titled Who Controls Your Crypto? Multisig, MPC, Custody Risk. A gold Bitcoin coin sits inside an open bank vault, while a gold key on a pedestal is linked by lines of light to three glowing people icons](https://joviantan.com/_img/images/insights/who-controls-your-crypto-multisig-mpc-custody-1920.webp)

Illustration. It does not show a real vault or custody system.

**In this article**

> **The big idea:** Owning an asset, controlling its private keys, and having a legally enforceable claim to it are three different things.

A crypto wallet does not hold coins inside a phone or hardware device. The blockchain records balances and transfers; a wallet manages the keys and signing process used to authorise transactions. The US Securities and Exchange Commission’s [Investor.gov](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins/crypto-asset-custody-basics-retail-investors-investor-bulletin-0) explains this distinction and outlines the trade-offs between self-custody and third-party custody.

That creates a deceptively simple question: **who can move the asset, who can change the rules, and who can restore access when something goes wrong?**

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#at-a-glance-five-layers-of-control)At a glance: five layers of control

 [![Diagram headed The digital asset custody control stack, an illustrative framework showing five linked layers. Legal rights: who is entitled? Governance: who changes rules? Signing: who can authorise? Operations: who can pause? Recovery: who restores access? Below: a secure design aligns all five layers, with technical controls, independent governance and tested recovery](https://joviantan.com/images/insights/custody-control-stack.png)](https://joviantan.com/images/insights/custody-control-stack.png) 

The custody control stack: five layers that overlap but are not interchangeable.

Layer

The question to ask

Example failure

Legal rights

Who is entitled to the asset, and under which agreement?

The customer’s claim is unclear during insolvency

Governance

Who can change limits, add signers or approve exceptions?

One administrator changes withdrawal policy

Signing

Who can produce a valid transaction signature?

A key or enough signing shares are compromised

Operations

Who initiates, monitors and pauses transfers?

A suspicious transfer is not stopped in time

Recovery

Who restores access after a loss or outage?

Recovery depends on one unavailable person

The layers overlap, but they are not interchangeable. A person can hold a private key without necessarily owning [the underlying asset represented by a token](https://joviantan.com/insights/you-own-the-token-do-you-own-the-asset). A customer may have a contractual claim against a platform while the platform controls the keys. A business can distribute signing power yet concentrate policy changes and recovery in one administrator.

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#1-hot-wallet-cold-wallet-or-third-party-custody)1\. Hot wallet, cold wallet, or third-party custody?

“Hot versus cold” describes connectivity. “Self-custody versus third-party custody” describes who manages access. They are separate choices: either custody model can use hot and cold arrangements. [Source: Investor.gov, 12 December 2025](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins/crypto-asset-custody-basics-retail-investors-investor-bulletin-0).

 [![Comparison headed Custody models: risk moves, it does not disappear. Self-custody: direct key control, owner manages recovery, key-loss and user-error risk. Exchange custody: convenient account access, provider manages keys, counterparty and access risk. Institutional custody: specialist controls may help, contract defines responsibilities, provider and legal risk. Below: ask who controls keys, policy, recovery and legal rights](https://joviantan.com/images/insights/custody-models.png)](https://joviantan.com/images/insights/custody-models.png) 

Custody models compared. There is no universal best choice.

Model

Typical control

What it helps with

Risk that remains

Self-custody

Owner manages the keys

Reduces dependence on a custodian

Lost keys, unsafe backups, phishing, mistaken transfers

Exchange custody

Exchange manages access

Convenient trading and account operations

Provider outage, account restrictions, insolvency, contractual risk

Independent institutional custodian

Specialist manages access under contract

Dedicated governance and operational processes may be available

Provider dependence, outsourcing, fees, legal and jurisdictional risk

Shared / co-managed

Multiple parties share defined responsibilities

Can separate initiation, approval and recovery

Confusing responsibilities, coordination failures, weak recovery design

A hot wallet is connected to an online environment and is convenient for frequent transactions, but that connectivity creates additional exposure to cyberthreats. A cold wallet isolates key material from ordinary online systems and can reduce some remote attack paths, but the device or backup can still be lost, stolen, damaged or mismanaged. Neither label proves that the full system is secure. [Source: Investor.gov, 12 December 2025](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins/crypto-asset-custody-basics-retail-investors-investor-bulletin-0); [Source: NIST, May 2020](https://csrc.nist.gov/pubs/sp/800/57/pt1/r5/final).

**The key distinction:** wallet type describes a technical arrangement; custody describes who has control and responsibility; legal documentation describes rights and remedies.

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#2-multisig-vs-mpc-two-ways-to-reduce-single-key-dependence)2\. Multisig vs MPC: two ways to reduce single-key dependence

 [![Conceptual diagram headed Multisig vs MPC. Multisignature: keys A, B and C feed a 2-of-3 policy requiring two valid signatures under wallet or chain rules. MPC or threshold signing: shares A, B and C feed a threshold protocol in which participants cooperate in a cryptographic signing protocol. Below: neither approach removes governance, implementation or recovery risk](https://joviantan.com/images/insights/custody-multisig-vs-mpc.png)](https://joviantan.com/images/insights/custody-multisig-vs-mpc.png) 

Multisig and MPC compared. Conceptual only: implementations vary.

### [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#multisignature-multisig)Multisignature (multisig)

A multisignature wallet requires multiple valid signatures under the rules of the blockchain, wallet script or smart contract. In a simple **2-of-3** setup, three authorised keys exist and any two are required to approve a transaction. This can reduce the chance that one compromised key is enough to move funds.

Implementation varies by blockchain. The way signers are represented, what is visible on-chain, transaction fees and recovery options all depend on the particular design.

### [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#multi-party-computation-mpc)Multi-party computation (MPC)

MPC is a family of cryptographic techniques that lets multiple participants cooperate in producing a signature without any one participant necessarily holding the complete private key in the usual form. Threshold-signature schemes are commonly used in digital-asset wallets.

MPC can allow the blockchain to see a conventional signature even though the signing process was distributed among participants. But its security still depends on the protocol, implementation, device security, independence of participants, access policy and recovery plan.

### [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#quick-comparison)Quick comparison

Question

Multisig

MPC / threshold signing

How is a transfer authorised?

Multiple signatures satisfy wallet or chain rules

Participants cooperate in a threshold-signing protocol

Is the internal process visible on-chain?

Depends on chain and implementation; multiple signers may be apparent

The chain may see a conventional signature, not the internal process

Does it eliminate insider risk?

No

No

Can it reduce single-key dependence?

Yes, if keys and signers are genuinely separated

Yes, if shares and participants are genuinely separated

What must be tested?

Threshold, signer independence, availability, scripts and recovery

Protocol security, share distribution, implementation, participant independence and recovery

Neither technology is automatically superior. A poorly governed MPC deployment can be weaker than a well-designed multisig arrangement, and vice versa. Vendor documentation can explain a particular implementation, but it is not independent proof that the system is secure. For example, BitGo’s [developer documentation](https://developers.bitgo.com/docs/wallet-types) describes wallet types and implementation choices across supported networks.

**Look beyond the acronym.** Ask who controls the policy, how approvals are separated, whether a single administrator can bypass controls, and whether recovery has been tested under realistic failure conditions.

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#3-the-hidden-concentration-of-power)3\. The hidden concentration of power

Distributing keys does not necessarily distribute control. Watch for these less visible single points of failure:

- One administrator can add or remove signers.
- One cloud or identity account can disable the signing service.
- One employee can change withdrawal allowlists or transaction limits.
- Multiple approvals rely on the same device fleet or identity provider.
- A recovery process lets one party reconstruct access without independent oversight.
- Monitoring detects a suspicious transfer, but nobody can pause it quickly.

 [![Map headed The custody risk map, with digital asset custody (keys, governance, operations, legal rights) at the centre, linked to five risks. Key compromise: stolen key or lost share. Insider abuse: privileged access. Operational failure: outage or failed recovery. Legal or counterparty: insolvency or jurisdiction. Policy concentration: one admin changes rules](https://joviantan.com/images/insights/custody-risk-map.png)](https://joviantan.com/images/insights/custody-risk-map.png) 

The custody risk map: evaluate the entire system, not only the wallet technology.

A robust system separates transaction initiation, transaction approval, policy changes, infrastructure administration and recovery. The separation should be real, not just multiple usernames controlled by the same person. Key management is a lifecycle problem: generation, storage, use, backup, rotation, recovery and retirement all matter. NIST’s [key-management guidance](https://csrc.nist.gov/pubs/sp/800/57/pt1/r5/final) covers protection of cryptographic key material and associated management controls.

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#4-what-happens-if-a-custodian-fails)4\. What happens if a custodian fails?

A wallet architecture cannot, by itself, settle legal or insolvency questions. If a custodian is hacked, [suspends withdrawals](https://joviantan.com/insights/binance-security-crisis-customer-trust), loses access to its signing infrastructure or enters insolvency, the customer’s outcome may depend on asset segregation, records, contracts, applicable law, the custodian’s location and how the service is structured.

A balance displayed in an app is not, by itself, proof that the customer directly controls specific on-chain assets. Ask whether you own the assets directly or have a contractual claim against the provider. Ask whether assets may be lent, pledged, reused or commingled, and whether your consent is required. [Source: Investor.gov, 12 December 2025](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins/crypto-asset-custody-basics-retail-investors-investor-bulletin-0).

In January 2026, Switzerland’s financial regulator [FINMA](https://www.finma.ch/en/news/2026/01/20260112-mm-am-01-26/) highlighted the technical, operational and counterparty risks of crypto-asset custody, noting that cross-border custody can add legal complexity if a custodian becomes insolvent. It emphasised the importance of robust infrastructure, appropriate oversight and clear protection for customer assets.

In Malaysia, the Securities Commission’s [Guidelines on Digital Assets](https://www.sc.com.my/regulation/guidelines/digital-assets) include a framework for digital asset custodians. The SC [describes digital asset custody as a regulated category](https://www.sc.com.my/digital-assets) and provides the applicable guidelines and registration information. The legal treatment of a particular activity depends on the facts and current rules, so businesses should check the latest official materials and seek qualified legal advice.

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#5-a-due-diligence-checklist-you-can-actually-use)5\. A due-diligence checklist you can actually use

 [![Checklist headed 12 questions to ask a custody provider, asking for evidence and not just assurances on each: key generation and backups, signing threshold and approvals, separation of duties, withdrawal controls, recovery testing, client asset segregation, lending and reuse permissions, independent security reviews, incident response, subcontractors and jurisdiction, insurance exclusions, exit and portability](https://joviantan.com/images/insights/custody-checklist.png)](https://joviantan.com/images/insights/custody-checklist.png) 

The 12-point custody checklist. The questions below explain each point.

Before choosing a wallet architecture or provider, get clear answers to these questions:

1. **Key generation:** How are keys or shares created, stored, backed up and retired?
2. **Signing threshold:** How many independent approvals are required? Who can change that threshold?
3. **Separation of duties:** Are initiation, approval, policy changes and recovery assigned to different people?
4. **Transaction controls:** Are there allowlists, limits, delays, out-of-band checks and escalation paths?
5. **Recovery:** What if a key share, device, employee or provider is unavailable? Has recovery been tested?
6. **Asset segregation:** Are client assets separated from the provider’s own assets in records and legal arrangements?
7. **Reuse of assets:** Can assets be lent, pledged, rehypothecated or otherwise reused? Is consent required?
8. **Independent assurance:** Are recent security assessments, penetration tests, audits and remediation records available?
9. **Incident response:** Who can pause transfers, contact customers, preserve evidence and coordinate with authorities?
10. **Subcontractors and jurisdiction:** Which third parties are involved, where are they located, and which law governs?
11. **Insurance:** What is covered, what is excluded, and who is insured? A headline limit is not a guarantee of reimbursement.
12. **Exit and portability:** Can assets be moved to another provider or self-custody? What happens during a dispute or outage?

If the provider cannot explain its controls in plain language, document responsibilities, and walk you through failure scenarios, treat that as a governance warning.

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#6-is-self-custody-always-safer)6\. Is self-custody always safer?

No. [Self-custody](https://joviantan.com/insights/can-crypto-be-frozen) reduces dependence on a third-party custodian, but places backup security, device protection, inheritance planning and transaction hygiene on the owner. Third-party custody may offer specialist operations and structured controls, but adds provider, contract, access and jurisdictional risks. Shared arrangements can distribute responsibility, while also introducing coordination and recovery complexity.

The appropriate model depends on technical capability, asset purpose, transaction frequency, governance needs, legal environment and tolerance for operational responsibility. For an organisation, a wallet should be managed like a controlled financial system, not treated as a simple app installation.

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#conclusion-follow-the-power-not-the-label)Conclusion: follow the power, not the label

“Cold storage,” “institutional custody,” “multisig” and “MPC” can describe useful components, but none is a complete security guarantee. The decisive questions are who can move assets, who can change the rules, who can recover access, whether customer assets are segregated, and what recourse exists if a provider fails.

Map the full chain: transaction initiation, approval, signing, broadcast, monitoring and recovery. Then test it against key compromise, insider abuse, staff absence, service disruption and insolvency.

> **You do not fully understand custody until you know who can sign, who can change the signing rules, and who can recover the assets when the system breaks.**

* * *

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#sources-and-further-reading)Sources and Further Reading

1. **U.S. Securities and Exchange Commission, Investor.gov, "Crypto Asset Custody Basics for Retail Investors – Investor Bulletin", 12 December 2025.** Wallets and keys, hot and cold wallets, self-custody and third-party custody, and questions to ask a provider. [Read the bulletin](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins/crypto-asset-custody-basics-retail-investors-investor-bulletin-0).
    
2. **National Institute of Standards and Technology, "Recommendation for Key Management: Part 1 – General", SP 800-57 Part 1 Rev. 5, May 2020.** Protection of key material and key-management controls. NIST also posted a public draft of Revision 6 for comment in December 2025. [Read the publication](https://csrc.nist.gov/pubs/sp/800/57/pt1/r5/final); [read NIST's key-management page](https://csrc.nist.gov/projects/key-management/key-management-guidelines).
    
3. **BitGo Developer Portal, "Wallet Types" and "Wallets Overview".** Vendor documentation, used only as an implementation example and not as independent security validation. [Read Wallet Types](https://developers.bitgo.com/docs/wallet-types); [read Wallets Overview](https://developers.bitgo.com/docs/wallets-overview).
    
4. **Swiss Financial Market Supervisory Authority (FINMA), "FINMA publishes guidance on risks associated with the custody of cryptobased assets", 12 January 2026.** The risks of crypto custody and the legal complexity of custody abroad. [Read the release](https://www.finma.ch/en/news/2026/01/20260112-mm-am-01-26/).
    
5. **Securities Commission Malaysia, "Digital Assets" and "Guidelines on Digital Assets", revised 19 August 2024.** The digital asset custodian category, registration information and the applicable guidelines. [Read the page](https://www.sc.com.my/digital-assets); [read the guidelines](https://www.sc.com.my/regulation/guidelines/digital-assets).
    

* * *

## [#](https://joviantan.com/insights/who-controls-your-crypto-multisig-mpc-custody#editorial-note)Editorial note

This article is for general educational purposes and is not legal, investment, tax or cybersecurity advice. Laws, regulatory requirements and legal outcomes vary by jurisdiction, asset type, contract and facts. Consult qualified professionals before making custody or business decisions.

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About the author

[Dr. Jovian Joris Tan Chern Chian](https://joviantan.com/about), professionally known as Dr. Jovian Tan, is a Kuala Lumpur-based technology entrepreneur and the founder and Chief Technology Officer of Bitara, working across blockchain, Web3 infrastructure, AI infrastructure and digital financial infrastructure.

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