How multisig works
The arrangement is written as M-of-N: N keys exist, and any M of them must sign. Each key is generated and held separately, by different people, devices or organisations.
One signer drafts the transaction and passes it to the others, who each add a signature. The network accepts it only when the threshold is met.
On Bitcoin, multisig is part of the scripting language. On Ethereum and similar networks, the wallet is a smart contract that holds the assets and checks the signatures, so the rules can include spending limits or time delays, and a bug in the contract is a risk of its own.
Where multisig is used
- Cold storage at exchanges and custodians, with signers in different locations
- Company treasuries, where no one person may move funds
- Shared custody: the client, the custodian and a recovery party hold a key each
- Admin keys of smart contracts, including the contracts that issue tokens
Multisig is public: the address type or the contract shows the set-up on-chain, and changing the signers means a new address or an on-chain transaction. Fees are higher than for a single signature, and support differs from one blockchain to another.
Multisig or MPC?
- MPC
- One key split into shares that produce a single signature off-chain. Nothing on the blockchain shows it, and it works the same way on every supported chain.
- Maker-checker approval
- An internal workflow in which one person proposes a payment and another approves it. Multisig is that control enforced by cryptography, not by the platform's software.
Where Multisig shows up in a platform
Modules that do the work
- Custody & walletsWallets on every major chain, with MPC custody from leading providers or your own keys.
- BackofficeOne console to run the platform: customers, money, risk, content and staff permissions.