Multisig
Multisig is a wallet where spending takes several keys at once, usually two of three. One stolen or lost key decides nothing.
What multisig is
The scheme is written as m of n: the address accepts a spend only with m signatures out of n possible keys. The most common setup is 2 of 3: two keys with you in different places, the third with a trusted person or a service. Any two together can spend, any single one on its own is useless.
For a miner this is closer to home than it looks. Pool payouts drip in regularly, savings grow, and a single key on a computer next to the farm is an invitation. A sensible scheme: a hot wallet for small expenses, multisig for the savings.
There is a price too. Transactions are more complex and slightly dearer in fees, setup takes care, and recovery is harder than usual: besides the keys you have to keep a description of the scheme, without it the wallet cannot be reassembled even with every key in hand.
The loss arithmetic at 2 of 3 is forgiving: one key gone does not touch the coins, you simply rebuild the wallet on the remaining two and change the scheme. Two keys gone is fatal, which is why copies get spread across geography.
Quick reference table
| Scheme | m signatures out of n keys, 2 of 3 is the common one |
| What it gives | one key cannot spend or steal |
| The price | trickier setup, slightly higher fees |
| What to keep besides keys | the wallet's scheme description |
| When it is fatal | losing two keys out of three |
How to spread the keys
Different devices: two hardware wallets from different makers are safer than two identical ones from the same batch.
Different places: home, office, a bank deposit box. Theft and fire come to one place, not three.
Keep the scheme description next to every key: it is not secret, nobody can spend with it, and recovery without it turns into a quest.
Once a year make a test spend with a small amount, so the scheme and the keys are proven before they are needed for real.
An example from practice
A farm's treasury is set up as 2 of 3: a hardware wallet at the office, a second in a bank deposit box, the third with a co-owner. Pool payouts go to this address once a week. Stealing any single device gives a thief nothing, and the weekly withdrawal takes two people five minutes to sign.
Related terms
Where to go next on the site
Coins
Numbers
Questions and answers
Does one person need multisig
Yes, a 2 of 3 scheme with keys in different places protects a solo owner against both theft and fire at once. The third key can sit in a deposit box, a trusted person is not required.
How much higher are the fees
A transaction with several signatures weighs more and costs more than a plain one, but next to the sums multisig gets set up for, the difference is negligible.
What happens if one key of three is lost
The coins are safe. With the two remaining keys you sign a spend to a new wallet with a fresh scheme, and the old address is retired.
How the terms connect
Every link in the chain is clickable. Orange marks where you are now.
Looking for an ASIC miner
The catalog holds 212 models. You can compare them by hashrate and by joules per terahash, then plug your own rate into the calculator and see what stays in your pocket.
Page written and checked by Denys Klimchuk. Updated .