// learn · season 02 · episode 07
Multisig — many keys, one vault
Episode 6 left us with an uncomfortable trade: cold storage defeats thieves and makes loss worse, because it still comes down to one key, one device, one human. The professional answer isn't a better hiding place — it's making sure no single key matters. The vault below uses three real keypairs; every signature it collects is genuine.
01 · the vault
Three keys, one rule
A multisig vault is an address with a policy attached: m of n signatures required. Set the rule, propose a payment, and collect signatures. Try executing early — the vault will tell you no.
any 2 of these 3 can move the funds; no single person can — and any one key can be lost without consequence
You
readyphone + hardware wallet
…
Co-founder
readytheir hardware wallet
…
Lawyer
readysealed envelope, offline
…
nothing queued — propose something for the owners to sign
02 · lose a key on purpose
The failure that stops being fatal
In episode 4, losing the key ended the story. Here it's a Tuesday. Kill one key and watch the vault shrug — then kill another and watch the shrug turn into something permanent.
✓ the vault still works
3 of 3 keys reachable · 2 needed
One key just died and nothing happened. That's the entire point: with the rule set to 2 of 3, a lost phone, a dead hardware wallet or an unreachable person is an inconvenience — not a catastrophe.
You
heldphone + hardware wallet
Co-founder
heldtheir hardware wallet
Lawyer
heldsealed envelope, offline
the dial, again
m-of-n sits between two opposite disasters. 1-of-3 means any single stolen key drains everything. 3-of-3 means any single lost key freezes everything. 2-of-3 is the classic middle: no one key can act alone, and no one key can destroy access. Try each rule above and lose a key to feel the difference.
the inheritance shape
Give the third key to a family member, a lawyer, or a professional custodian and the arrangement changes character: they can't touch anything alone, but together with one other keyholder they can reach the funds when you no longer can. It's succession that doesn't require handing over control today — which is why this shape, not a hidden envelope, is what serious estate planning for digital assets looks like.
03 · two flavors
Bitcoin multisig vs Gnosis Safe
The same idea — m of n — implemented in two very different places. One puts the rule in the lock on the coins; the other puts it in a program that holds them.
Bitcoin multisig
script-levelThe rule lives in the script that locks the coins (P2SH / P2WSH). The address itself encodes “2 of these 3 public keys”.
- — Signatures are collected off-chain: a partially signed transaction (PSBT) is passed from signer to signer, then broadcast once as a single transaction.
- — Changing the owners or the threshold means creating a new address and moving the funds to it.
- — No on-chain queue — coordinating who signs next is the wallet software's job, not the chain's.
- — Works across hardware wallets from different vendors, which is itself a security property: no single manufacturer holds all the risk.
Gnosis Safe
smart contract · EVMThe vault is a smart contract. Owners and threshold are on-chain state that the contract enforces on every transaction.
- — Owners and threshold can be changed by transaction — add a signer, raise the threshold — without moving the funds anywhere.
- — Proposals live in a queue and collect signatures on-chain, so everyone can see what's pending and who has signed.
- — Extensible with modules and guards: spending limits, allowances, recovery arrangements, automation.
- — Executing costs gas, and someone has to pay it — the contract is a program, and programs run on someone's dime.
what they share
Neither is automatically “safer”. The security lives in how many keys, who holds them, and where those keys live — everything you learned in episodes 5 and 6 still applies to each key in the vault. Multisig removes the single point of failure. It does not remove the humans, and it quietly adds a new job: someone has to keep track of who holds what, and make sure that's still true in five years.
04 · what multisig costs
Nothing is free, including safety
it's visible
On-chain, a multisig vault usually announces itself as one — including how many signers it has. That's a privacy cost, and occasionally a targeting one.
it needs coordination
Every signer needs working tooling, a reachable device, and the willingness to use it — at 2am, on holiday, years from now.
it can be rigid
On Bitcoin, changing who holds keys means moving the funds. On EVM chains it's a transaction — but a transaction someone must pay for and get signed.
Which raises an interesting question. Multisig makes many signatures and shows them to the world. What if you could have many people — and still produce just one perfectly ordinary signature, with the private key never existing anywhere, not even for a moment? That's episode 8, and it's how most institutional custody actually works today.
next up
Episode 08 — MPC: the key that never exists play now →Split a secret, sign together, and never assemble the key at all — the season finale.