Multisig

User flows

Wallet creation

Key creation
Key sharing
Wallet creation

Transacting

Transaction creation
Transaction sharing
Transaction signing

User notifications

A transaction was sent/received
Wallet owner asked you to sign this transaction
The other wallet owner(s) have made a transaction
There were transaction in this wallet that were not initiated by this device

Terminology

Shared wallet
Collaborative wallet
Vault
Team wallet
Multikey wallet

Planning considerations

How many people participate?
Who should be able to initiate transactions?
What device is used for coordination?
What devices are used for signing?

Setups

2-of-2 2FA
2-of-3 1 owner with 3 hardware devices
2-of-3 1 owner with 1 hardware device + 2 people with wallet apps
2-of-3 3 owners

Do's

Use separate devices for the wallet and each key

Don'ts

Bring together participating wallets on the same device