What is Multisig (Multi-Signature)

Multisig (multi-signature) is a cryptographic security mechanism requiring more than one private key to authorise a cryptocurrency transaction. Rather than a single key controlling a wallet, multisig distributes control across multiple keys providing protection against single points of failure, theft, and insider misconduct.

HOW MULTISIG WORKS

A multisig wallet is configured with an M-of-N scheme: N total keys are associated with the wallet, and M of those keys must sign any transaction for it to be valid.

Common configurations:

2-of-3: Three keys exist; any two must sign. Most common for personal security, one key on hardware wallet, one on secure cloud backup, one with a trusted party. Lose one key and you can still recover with the other two.
3-of-5: Five keys exist; three must sign. Used by exchanges, DAOs, and organisations requiring distributed approval.
4-of-7: Enterprise-grade treasury management requiring majority consensus.

USE CASES FOR MULTISIG

Exchange and Institutional Custody: Major exchanges use multisig wallets to store customer funds.
No single employee can unilaterally move assets; multiple signatories from different departments or locations must cooperate. This prevents insider theft and reduces single-point hacking risk.
DAO Treasuries: Organisation treasuries managed by elected multi-sig signers (typically 4-of-7 or 5-of-9). Gnosis Safe (now Safe) is the most widely used DAO multi-sig, securing billions in protocol treasuries.

Personal Cold Storage: Using a 2-of-3 or 3-of-5 personal multisig across a hardware wallet, secure paper backup, and a trusted family member's hardware wallet.

MULTISIG PLATFORMS

Safe (formerly Gnosis Safe): Most widely used Ethereum multisig. Manages billions in DAO and institutional funds.
Electrum: Built-in Bitcoin multisig wallet.
Casa: Consumer-focused Bitcoin multisig service with key management support.

THE WAZIRX HACK LESSON

WazirX's July 2024 hack resulted in $235 million in losses from a multisig wallet. Attackers used social engineering to manipulate the signing process, demonstrating that multisig security depends entirely on the security and vigilance of each keyholder. Multisig reduces but does not eliminate risk when signers are compromised through phishing or social engineering.

Terms in addition to the Multisig (Multi-Signature)

Blockchain

A blockchain is a subset of a distributed database. The Bitcoin inventors originally prototyped the system in 2008. This modern database is made up of separate blocks that are connected together in a chronological chain. Blockchains may be used to store a wide range of data types. It has mostly been utilized as a public ledger for bitcoin transactions to date. A peer-to-peer network comprised of independent nodes uses a consensus process to ensure the blockchain's security and legitimacy. Each node in the network keeps a public and immutable copy of the data.

2 Factor Authentication (2FA)

2 Factor Authentication is a security measure with two layers. It is used by the majority of cryptocurrency exchanges. To log in, you must provide not only a password, but also a code obtained, for example, from the Google authenticator.

Airdrop

An airdrop is a method of distributing coins. End users can typically obtain coins for free or in exchange for doing a small task, such as subscribing to a newsletter, sending a tweet, or inviting others via a personal affiliate link. Cryptocurrency airdrops — the act of depositing cryptocurrency into public crypto wallets — are utilized as a marketing, liquidity creation, and network bootstrapping technique for many different types of blockchain initiatives.

Altcoin

Altcoin - "alternative coin" - is any kind of digital currency other than Bitcoin. Since the launch of Bitcoin, the world's first digital currency, many altcoins (as well as supporting blockchains) have been created. Altcoin digital currencies share many similarities to Bitcoin, but consistently and have significant differences. There are about 20,000 altcoins, and this number is expected to grow significantly in the coming years. Altcoins often develop Bitcoin features. Ethereum, currently the most widely used blockchain, supports digital contracts and separate applications where Bitcoin does not. Altcoins are also often created to cater to the needs of different users. The Litecoin blockchain, for example, can process payments quarterly for the duration of Bitcoin.

Cold Storage

Cold storage is the way to store cryptocurrency offline. The word refers to the use of offline wallets that are not connected to the internet. Cold storage is the most secure way to keep cryptocurrencies since an offline currency becomes less likely to be hacked and stolen. Paper wallets, printed renditions of private keys, and offline hardware and software wallets are all examples of cold storage.